Change to use metric annotation's simple name for the name of an
un-named metric to avoid collisions on names when a class is annotated
with multiple unnamed metrics.
Provide the ability to set the metric registry to child classes of this
module
Mark Listener classes as public so that they could be included through a
different module.
Remote the static define
Return the metric registry to private
Merge remote-tracking branch 'origin/fix-access-to-metricsregistry'

Conflicts:
	src/main/java/com/palominolabs/metrics/guice/MetricsInstrumentationModule.java
Merge remote-tracking branch
'origin/fix-multiple-metrics-with-same-name'