Submodularize nimble

In an effort to make Nimble deployable, we've refactored the file structure of Appception to use Mozilla's Nimble  as a submodule.

There are immediate options if it doesn't deploy:

1) Inspect the end of the Gruntfile or CONTRIBUTING.md for install instructions, and create some process for Azure to run those scripts.
  NOTE: This might be difficult because those scripts need to be run from inside the 'nimble' directory, and I get the feeling that scripting directory changes might be tricky...?

2) Completely download nimble AND all its subomdules and push them to our repo, and serve it.
  NOTE: this might have 2 advantages:
  1) Potential customization of extensions and themes.
  2) Minification of the Nimble code (though it serves quickly already)