Prevent backbone.js example from unnecessarily polluting the global namespace.

Added :focus styles to clear link to allow for keyboard navigation

tab to the "clear all" link. Only CSS was changed save fidel, which needed an
href on the link to allow tabbing to it.  I did not edit source (less,scss)
files.

Implemented a new SpineJS version using CoffeeScript with the latest SpineJS 1.0.5

updating sproutcore example to emberjs. Minor changes in namespacing required. Switch from parentViews as required by last release of SC

Added an example for Backbone.js and Require.js

ExtJS 4 Todo addition

jQuery example - added count on Clear button

Also some selector caching and other small optimizations.

Adding jQuery-only todo example. This will be more clearly made available in TodoMVC 0.3 along with the other new examples coming soon.

Quick once-over of the grammar/punctuation in the README