Prep v2.3.4 release

Removed "batchable:" prefix from batchable task description.

Prep v2.3.2 release

Prep v2.3.1 release

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