Remove sample gradle builds

Remove sample gradle builds since they are not run during the regular
build and would need to be manually updated after a release.
Increase SampleIntegrationTests run timeouts

Increase the timeouts to give CI builds more time should dependencies
be missing.
Rework POMs to support automated CI release
Add Javadoc aggregate project

Add a Maven project to aggregate appropriate Javadocs into a
consolidated set.
Update travis build