Generic back button

Read the inline docs. Basically we add a simple back button
which calls history.back when calling showView. There are
quite a few edge cases covered here. eg. don't show the back
button on the first page the user visits (e.g deep linking)
Generic back button in the courses app
Fixed tests

Still need tests for the generic back button stuff though
Added jasmine-jquery plugin
Added pageStack to the App object

This way it can be accessed externally (eg. testing)
Add jasmine-jquery to require.config
Require jasmine-jquery

Since it's a plugin it's a bit easier to require it upfront
this is because its functionality is exposed through the
existing jasmine object
Added tests for back-button behaviour

These tests include a html fixture
Merge pull request #12 from ox-it/generic-back-button-support

Generic back button support