Add optional 'key' argument to $remove
Move usage info to seperate docs page
Merge pull request #152 from jeffbcross/omnibinder

feat(omnibinder): added omnibinder protocol base & karma
Seperate out e2e and unit tests, update gitignore
fix for $priority resetting to .priority, with e2e test.
Merge pull request #153 from mchcoastal/v2

fix for $priority resetting to .priority, with e2e test.
Minor formatting changes
Add AngularFireAuth integration as the "$firebaseAuth" service
Update $firebaseAuth method names to match $firebase
feat(mock): added firebase mock for unit tests
feat(subscribe): added subscribe init tests
Seperate out e2e and unit tests, update gitignore
gitignore: ignore bower
feat(child_added): implement child_added indexing
feat(onProtocolChange): implemented calling binder.onProtocolChange
feat(objectGenerators): added factories to generate change objects
chore(bower): add observe-js to bower
feat(protractor): add protractor plus basic e2e test for omnibinder