Update readme and java doc for 1.21 release

Update javadoc for 1.20-SNAPSHOT

Merge branch 'trunk' for 1.19 and prepared release

Prepare 1.18 release

Merge branch 'trunk'

Update pom.xml

Release 1.15

Merge 1.14 snapshot into master for release

Conflicts:
	README.md
	pom.xml

Update readme for 3.13 release

Update readme for 3.13 release