Publish to canary branch of components/ember-data repo.

PR should allow for publishing to channels beta/release/canary just as Ember.js does it.  The main script added here is adapted from Ember's [bower_ember_build ](https://github.com/emberjs/ember.js/blob/master/bin/bower_ember_build) which was introduced in this [PR](https://github.com/emberjs/ember.js/pull/5041) which outlines how the steps to follow to get it working with travis. 

Also abstracted a small utility function to find `versionStamp` for use during the `copy:bower` step.  And removed the task for setting `versionStamp` in favor of simply setting it within the `Gruntfile`. 

Please let me know if you have any questions or would like to pair during testing and or merging.  :))

[Closes #2062]