Started updating email/password tests

Also addressed some of Michael’s code review feedback
Merge branch 'master' into email_pw_tests
Added tests for creating, removing, changing, and email resetting passwords
Finished initial test coverage for email/password provider
Merge pull request #48 from firebase/email_pw_tests

Added tests for email/password provider
Flipped validate flag for calls to validateCallback
Merge branch 'master' into v1-6-3
Added tests for arg count changes