fixing parentheses mismatch in the getting started guide.
Corrects servlets package name (c.c.m.servlets, not c.c.m.servlet)
documentation correction: MetricRegistry, not MetricsRegistry.
Merge pull request #407 from futures/fcrepo-snapshot

Corrects servlets package name (c.c.m.servlets, not c.c.m.servlet)
Merge pull request #406 from pcsanwald/master

Fixing small typo in getting started guide
InstrumentedHandler: Remove duplicate calls to activeRequests.dec().

The counter is decremented inside updateResponses(). This caused the
active-requests counter to be negative.
Merge pull request #408 from evanj/master

InstrumentedHandler: Remove duplicate calls to activeRequests.dec()