Merge pull request #1708 from rjackson/dont-blow-up-shitty-browsers

Object.create does not exist in old IE.
Remove restriction for jQuery version in bower.json

This was needed since Ember v1.3.1 only works with jQuery <2.1, but the
bower config for this version didn't specify this restriction. Since
this has been fixed by Señor @rjackson (http://git.io/B2xRbQ) the
specific jQuery version is removed again from `bower.json`.
Merge pull request #1710 from pangratz/remove_jquery_dependency_in_bower

Remove restriction for jQuery version in bower.json
Allow testing against multiple versions of Ember & jQuery.

* Adds ability to test against multiple versions of Ember via the
  `emberchannel` query param (defaults to local Bower version).
* Adds ability to test against multiple jQuery versions via the `jquery`
  query param (defaults to local Bower version).
Enable multi-channel testing.

Adds the following tasks:

* `test:local` (alias to previous `test` task)
* `test:release` (tests against current release builds of Ember)
* `test:beta` (tests against current beta builds of Ember)
* `test:canary` (tests against current canary builds of Ember)
* `test:all` (tests against all channels of Ember)

Changes the default Travis test script to `test:all`.