[Process manager] Added debug MD.
#1409: using gitbook for documentation. See how to install and run/build at https://github.com/GitbookIO/gitbook
[Java container] Added jarUrl option to JavaContainerConfig.
[Java container] Refactored ProcessManagerController to improve its testability.
[Java container] Added ProcessManagerController tests.
[Java container] Added Javadoc.
[Java container] Added extra logging.
Added support for description field in Versions.
Added karaf `version-info` command.
Verified that doesn't break hawtio.
[Java container] $FABRIC8_JVM_ARGS overrides etc/jvm.config