Simplify InstrumentedEhcache a bit.
Update Ehcache docs.

Add XML config back in when #358 is fixed.
Updated metrics-jdbi docs.
Tabs. Wat r u doing. Tabs. Stahp.
Trim metrics-jersey docs.

Add XML config back in when #359 is fixed.
Updated docs for metrics-log4j.

Add XML config back in when #369 is fixed.
Update docs for metrics-logback.

Add XML config back in when #368 is fixed.