OnTopic Data Transfer 2.0.0 is a major release primarily focused on s…

…upport for OnTopic 5.0.0's new topic references feature. It includes changes to the JSON serialization format—though it also maintains backward compatibility with the legacy format.

New Features
- Full integration of OnTopic 5.0.0's new topic references feature, including support for `BaseTopic` and merging topic references based on `LastModified` (2cfbc52, d0cb983).
- The `Import()` now tracks any associations that it is not able to resolve and attempts to resolve them after the initial `Import()` has completed, thus accounting for associations to topics that weren't yet imported because they occur later in the interchange data (4a75ff6). This prevents the need for calling `Import()` twice to ensure that there aren't any unresolved associations.
- Configured `SourceLink` with references to GitHub commits so that packages can be properly debugged by implementers (8e1a5cc).
- The NuGet packages now include the XML documentation, thus allowing implementers to benefit from IntelliSense annotations in Visual Studio (cbc66d4).
- Added icon to NuGet packages to make them easier to recognize, and consistently branded (d65a81a).

Breaking Changes
The following changes impact the interchange format, but maintain backward compatibility for derserializing legacy JSON files.
- Marked `DerivedTopicKey` as deprecated, and no longer write it during `Export()` (4705b29, 6c33fb8).
- Renamed `AttributeData` to `RecordData` and `AttributeDataCollection` to `RecordDataCollection` to maintain parity with the `TrackedRecord(Collection)` in OnTopic, and to provide base support for both attributes as well as topic references (a5df9b1).
- Renamed `RelationshipData` to `KeyValuesPair` and `RelationshipDataCollection` to `MultiMap` to maintain parity with the `KeyValuesPair<T>` and `TopicRelationshipMultiMap` in OnTopic (bc15631). The JSON now writes to `Relationships: [{ …, Values: […]}]` instead of `Relationships: [{ …, Relationships: […]}]`.

Code Improvements
- Updated to OnTopic 5.0.0, with accommodations for breaking changes, such as the rename of `Topic.DerivedTopic` to `BaseTopic` and `Topic.Relationships.SetTopic()` to `SetValue()` (2f75a73).
- Updated to `System.Json.Text` 5.0.0, which allows us to take advantage of .NET 5 annotations, such as `[JsonInclude]` and `[JsonIgnore()]`, while maintaining compatibility with .NET Core 3.x (439b41c).
- Implemented the latest version of Microsoft's code analysis library (`NetAnalyzers`), as well as the feedback it exposed, including nullable reference annotations (7fa983c).

For full release notes, see #1.

Version 1.2.1

Minor maintenance release with an emphasis on updating the code to utilize new C# 9.0 capabilities and apply the latest version of code contracts. While some of these updates may improve reliability, they do not resolve any known bugs or introduce any new functionality.

Updates
- Updated development dependencies, including GitVersion and the .NET Test Framework (89fd11e)
- Updated to C# 9.0 and implemented some new syntax capabilities such as implicitly typed constructors and improved pattern matching (5e34b68)
- Updated to new `Microsoft.CodeAnalysis.NetAnalyzers` and implemented new recommendations (d81de85)
- Marked assemblies as CLS Compliant (6f05bd9, 7b8227a)

1.2.0 Release

This update builds off of OnTopic Library 4.3.0 in improving performance and reliability when importing and saving large topic graphs. Most notably, this includes the ability to dynamically update the content type and attribute schemas based on the in-memory topic graph, thus addressing potential conflicts between the current configuration and the imported configuration. This is especially critical when bootstrapping an empty database with a reference configuration, which is now supported. In addition, a number of updated have been made to better maintain referential integrity, such as support for implicit topic references—i.e., references that point to other topics. Those are now translated to unique topic keys on `Export()`, and then translated back to topic identifiers on `Import()`.

Features
- Support translating implicit topic references from `Topic.Id` to `Topic.GetUniqueKey()` on `Export()` (0993ea3) and then back to `Topic.Id` on `Import()` (37d7a82) in order to maintain referential integrity of topic references saved as attributes (2467351); this can be controlled through the new `ExportOptions.TranslateTopicPointers` option (b32304b).
- Built-in support for resolving explicit references (such as relationships and `DerivedTopic`s) which point to topics which haven't yet been `Import()`ed; the `Import()` will attempt to resolve these once the graph has been fully imported (96f1473).

Bug Fixes
- Fixed bug in which `ParentID` and `TopicID` were included as part of `Export()`, which introduced referential integrity conflicts on `Import()`; this could result in `DerivedTopic`s being updated to point to different topics (60ab46b).

Code Changes
- Updated `Export()` to use newly centralized `Topic.GetByUniqueKey()` extension method instead of its own local helper function (930538e).
- Updated `Import()` to use newly centralized `AttributeValueCollection.IsDirty()` instead of its own locally defined logic (b9143a5).
- Updated `Import()` to use newly created `Topic.IsNew` property for detecting if topic references are valid (94f1efc).

Maintenance
- Updated various internal dependencies

Release 1.1.0

This release fixes critical bugs from 1.0.0. The most notable of
these is that `ContentType` would be deleted when performing a
replace, thus failing on save. There were also several issues
with recursion. For example, the `ImportStrategy` was not being
relayed to children during import. Worse, there was a bug which
prevented `DeleteUnmatchedNestedTopics` from being working
correctly; this further prevented `ImportStrategy.Replace` from
operating as expected.

In addition to these critical bug fixes, this version also
incorporates new support for `LastModifiedImportStrategy`, which
permits the attribution attributes, such as the byline
(`LastModifiedBy`) and dateline (`LastModified`) to be updated
independent of the general `ImportStrategy`. This allows, for
example, any updates topics to be attributed to the current user
and the current time, regardless of what the source or target
values define.

Release 1.0.0 of OnTopic Data Transfer service

The OnTopic Data Transfer Service provides tooling to enable
basic exporting and importing of topic graphs via a JSON
interchange format, as well as an intermediary set of data
transfer objects.

As importing is subject to a number of  considerations, the
service also includes an `ImportOptions` object which permits
the caller to control how the import is done. For example, they
can choose to only add new items, to merge with existing items,
or to replace the entire tree.

The Data Transfer Service does _not_ provide a GUI; it will be
up to downstream providers, such as the OnTopic Editor, to
expose a user interface for this functionality.