Speed up tests
Close #299 Configurable actor anchoring
Close #301 Particle emission rates can be less than 60
Close #279 Make blink better
Close #288 add and remove overloads for entities in excalibur
Refactor anchor to be simpler
Close #307 Default original opacity to color alpha
Merge pull request #308 from excaliburjs/dev-erik

Merge anchoring, particle fix, blink fix, implement add/remove overloads, opacity fix