Move all the API files into plugins/core.

Some of them are no longer necessary and have been deleted.
Separate chrome.fileSystem into a plugin.
Modernize storage and turn it into a plugin.
Make socket into a plugin, and use the new plugin dir structure
Modernize the main Chrome API Javascript files and make into a plugin

Includes splitting chrome.Event into its own module (plugins/common)
Chrome plugins now fully installable on the cordova-cli prototype

Move plugins/core to plugins/bootstrap
Move third_party into plugins/spec and update plugin.xml
Eliminate grunt, it's no longer necessary.
Add plugin to handle chrome-extension URLs for Android.