Revert "Migrate to Browserify / Gulp for Build Process"

Reverts mozilla/localForage#227.

Actually, it seems the test are failing locally for me.

Perhaps we need more elaborate build instructions; it would help if you started in the README and changed the grunt sections to gulp instructions.

![screenshot 2014-08-10 18 27 04](https://cloud.githubusercontent.com/assets/90871/3870765/7d1e0206-20dd-11e4-85e9-2ceb41c3feb7.png)