Swappable IO layer for MetadataCache.
includes parameterized tests.
Swappable IO layer for ShardState.
stub in a io-datastax module.
Method renames
resolve merge conflicts
Merge branch 'master' into swappable_io
Merge pull request #287 from gdusbabek/swappable_io

Swappable IO for MetadataCache and ShardState* services
fix test-state test failure.
move appender factories into their own submodule.
update copy right on two poms.
fix merge conflict
Merge pull request #293 from gdusbabek/dropwizard_log_appenders

Include custom slf4j logging appender factories in blueflood
Add instrumentation to MetadataCache
Add some more metrics, fix typo
Change name of a metric
Add locator to cache size
Make Type and unit processing configurable
Fix the name of metric registry
Catch exception with metric registration
DISABLE_TYPE_UNIT_CACHE_READS