Increment patch-level version number: v1.13.1 --> v1.13.2

Fix comment

Increment patch-level version number: v1.13.0 --> v1.13.1

Add support for public-key authentication

- Add support for storing RSA public keys (in PKCS#1 or PKIX
  representation) in user accounts.
- Implement public-key authentication using RSA-PSS in server and CLI
  client.
- Add commands for key management on the server side.
- Add commands for public-key based authentication to the CLI client.
- Several small bugfixes and improvements regarding CLI interaction and
  synchronization / locking.
- Update and improve protocol specification.
- Update and improve README.
- Increment minor version number: v1.12.0 --> v1.13.0

Implement device tokens and improve interface to web server

- Device tokens allow for easier integration with third-party applicatoins
  and devices.
- Improve web server integration. Specifically, allow for status codes other
  than "HTTP 200 OK" from CGI calls.
- Update and improve documentation.
- Increment minor version: v1.11.3 -- v1.12.0

Implement certificate validation in CLI client

Update version number to v1.11.3

Small fixes / improvements in multipart reader

Increment patch-level version number: v1.11.1 --> v1.11.2

Fix documentation (README.md)

Add initial command-line client and fix support for GeoDB clearing

- Fix bug in session handling.
- Some code restructuring / improvements, including rework of "filter" and
  "geoutil" modules to make use of new Go features regarding timestamp
  handling.
- Rename "binary" file format to "opengeodb" for consistent naming.
- Implement mechanism to safely clear geographical database from within web
  interface and add separate "geodb-clear" permission. (This feature was
  added in v1.9.0, but was not implemented completely.)
- Increment minor version number: v1.10.0 --> v1.11.0

Add support for clearing the geographical database

- Users will have to provide a SHA-512 hash of the database contents (in
  OpenGeoDB format) in order to clear the database. This serves as a
  protection against accidental deletion of data.
- Web interface is updated to allow the user to perform the action and
  provide the required hash value.
- Update readme.
- Increment minor version number: v1.9.0 --> v1.10.0

Add support for import of OpenGeoDB format

- Implement OpenGeoDB importer.
- Add the relevant UI options for selecting OpenGeoDB format for import.
- Update descriptions of existing export formats in the UI in order to match
  the respective import options.
- Update readme.
- Increment minor version number: v1.8.6 --> v1.9.0