osgi-bundles: add new logger bundle

This new logger bundle listens to registered LogReaderServices and
delegates log entries to slf4j.
This works well with Apache Felix Log for example.

If one doesn't install any LogReaderService, one can fall back to using
osgi-over-slf4j.

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
osgi-bundles: remove unused type parameter in OSGIKillbillRegistrar

The parameter wasn't used. This may fix the compilation with javac 1.6.0_24.

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>