fix .dfp() did not return a jquery collection
add ability to monkey patch window.googletag

So far, I've only used it to override googletag.display.
Useful for ads that aren't in doubleclick yet, for debugging css, and
creating live mocks.
Merge pull request #19 from crccheck/add-return-this

fix $(selector).dfp() did not return a jquery collection, not chainable.
Merge pull request #21 from crccheck/monkey-patch-googletag

Add ability to monkey patch window.googletag
Refactored, Re-minified, bumped version

- Refectored extension of options to be a deep merge
Started refactor of code

Breaking up code to be more functional and adding a few more features.
Re-minified
Merge pull request #22 from coop182/refactor

Refactor