Fixed plugin initialization during startup. Fixes #1195
Refactored log4j2 config for better logging.

The default logging level from FML package is now INFO. If you require more
output in FML logs, open jar and edit the log4j2.xml in root then change
FmlFile's logging level from INFO to something else such as TRACE or DEBUG.

* Fixed getBukkitVersion returning Unknown-Version. Fixes #1205