Add gitignore file

Ignores Eclipse artifacts and the maven target
Update FCrepo dependency versions to 3.6.2.
Replace Apache Commons logging with SLF4J logging.

Apache Commons logging has been explicitly excluded in the FCrepo POM
files as of 3.6.x, necesitating these code changes to use the SLF4J
logging library.
Merge branch 'lyr-master' into 6.x