chore(grunt): adds grunt-conventional-changelog plugin

this plugin lets you auto-generate changelogs based on given commit
history

you commit messages have to follow the same conventions that are used
in this commit

for more information see http://github.com/btford/grunt-conventional-changelog
Add value event handler to $on
Save priority for top-level node before switching to child events, fixes #243
Add _parseObject call to $set so priorities are preserved, fixes #228
Add bower and grunt badges to README
Add $id to object provided by $firebase, fixes #187
Change observe-js to official bower version
Prevent loaded event from being called multiple times, fixes #237
Remove noLogin option from $createUser, fixes #235
Make $on chainable
Move angular-mocks and observe-js to devDependencies
Fixed some typos
Fixes #255 - orderByPriority always returns an array
Add method $getRef to $firebase objects, fixes #252
Add note to fix second timeout by referencing Github issue
Add $update method, fixes #238
bump version to 0.7.0
#time 10m

* Reapplying customJWT patch to angularFire 0.7.0