Prep v2.3.0 release

Fixed link to parseq-batching contrib project in README.

Fixed bug in ShallowTraceBuilder that could cause NPE when getTrace()

was called and task was cancelled at the same time.

Prep v2.1.2 release

Prep v2.1.1 release

Filled out CHANGELOG before 2.1.0 release

Prep v2.0.8 release

Increased delay in tests to avoid failing on overloaded machines.

Prep v2.0.6 release

Prep v2.0.5 release

Prep v2.0.4 release