Fixes for JSON serialization issues of GROOVY-6937 and GROOVY-6852
GROOVY-6973: Add backport jars facility
Add missing pom file
Produce dummy javadoc/sources jars for backports, for Maven Central to be happy
Fixed missing backport jars from artifactoryUpload
GROOVY-6976: after upgrading to 2.3.5 CliBuilder doesn't work