Added issue count to the template

This checks uses the GitHub API to fetch the number of open issues for a specific implementation, updating the side-bar accordingly.
Fixed code style issues

Added .jshintrc from ToDoMVC https://github.com/tastejs/todomvc/blob/master/.jshintrc
The code which was taken from underscore is jshint ignored rather than fixing jshint violations.
Moved fetchIssueCount function to the Learn prototype
The new 'issues' section in the learn bar is hidden by default

The issues section is only shown when the API reports >0 issues for an implementation
Added null check to make migration easier

This check means that the script will not fail if learn.json is not updated at the same time as todomvc-common
Merge commit 'e93b7aacad84d3412d63019ff62272e1101a8417'

Conflicts:
	base.js
Issue label now uses the framework name

Previously the issue label was derived from the URL, now it uses the framework name from learn.json.
Added a check to ensure that the data returned by the GtHub API is an array
Text changed to 'The app has (n) open issues'
Merge pull request #10 from ColinEberhardt/master

Added issue count to the template