Protractor support & platform configs

There's a lot going on here.

- added protractor configs to the grunt file
- added a custom task to handle creating the support directory. it downloads the node-webkit chromedriver, extracts it, and creates the necessary symlink to run protractor.

There were a few platform-specific files to manage so I created a `config.platform.json` file and a node module `src/lib/pconfig.json` to take the platform config and return properties relevant to the local system.

`grunt protractor-setup` will run the setup, and it will run before `grunt e2e` as well. It will short out if it finds the  required files to move head.

The one thing I couldn't get working was `fs.chmodSync()`. The `test/support/chromedriver` needs to be executable, but that function was not doing it. You have to manually chmod it for now.