Merge pull request #83 from hughsimpson/type-filter-on-actor-count

Type filter on actor count
Can run 'sbt prePublish' to print 'Hello World'
java main example for akka
Extra tags for looking at counts
All tests, except new test suite, passing. 3 new tags for actor creation.
Removing legacy code
Don't append null 'uncheckedClassName' to a String for datadog tag! Share common logic between actor creation monitoring and actor death monitoring
Test is still incomplete. We sanatize tag strings before sending to Datadog
Actors Just Won't Die
Test passing: can proved that included/ exc;uded filters work for unnamed anonymous inner class actors without alteration
Addressing some comments
Rebasing from upstream