Refactored pubsub service into a non class. pubsub no longer sends
log messages on subscribe
Added file for data_stream tests
Merge branch 'master' into refactor-pubsub

Conflicts:
	lib/pubsub_service.js
Refactored pubsub into non-static class, updated dependants and tests
Merge branch 'master' into refactor-pubsub
Fixed typo
Merge pull request #13 from zettajs/refactor-pubsub

Refactor pubsub