Migrate to android studio

Alrighty, so after surprisingly not that much fiddling around, I've managed to port the project over to Android Studio. I'm happy enough to trash this if not everyone is in favour of it, but I do have it working. 

### Pros
- No more eclipse
- Gradle builds
- App is way way easier to get set up with
- We can build the app on TravisCI (https://travis-ci.org/smap-consulting/sms-smap-gateway)
  - Can show travis CI build badge on the readme, giving us open source rep-points
  - more info on travis integration http://docs.travis-ci.com/user/languages/android/
  - we get build badges on pull requests (travis pulls down the PR, does the merge and runs the build for you to make sure that if you merge it in, it'll still be all good)
- We can start writing tests and running them in CI
- No more fixing borked build paths as build path is configured in the `build.gradle`
- No more vendoring popular .jars, can pull them straight from maven
- Makes it much easier to drop in things like these http://square.github.io/
- Can start running builds against the HEAD version of the survey-manager library with a bit of legwork
- We can start building .apks and uploading them wherever as build artifacts
- Android studio has a dark theme built in without having to install any whack plugins
- Its supposedly the future of android
- Still works fine with Genymotion with [the official plugin](http://plugins.jetbrains.com/plugin/7269?pr=idea)
- Sweet [Automated refactorings](http://www.jetbrains.com/idea/features/refactoring.html)
- Way better completion support and linting support
- The IDE remains in sync with the file system, eg. don't have to refresh the project every time you `git pull`

### Cons
- Android Studio is still in Beta (which is actually moving forward, as it was in preview until GoogleIO 2014)
- Everyone has to set up the project again
- I have only tested this on OSX so far, so not sure if it's fiddly on Windows / Linux
- New keyboard shortcuts to learn
  - There is a built in keymap though that is based on eclipse shortcuts
- Have to download some stuff again, eg ADT etc.
- Might need to write a tiny bit of documentation on the README with setup instructions
- Probably won't work super well in eclipse after these changes
- No NDK Support (don't think this is a problem for us though)
- We'd probably have merge to any pending (or soon to be) PR's first, then update those changes back onto this branch as there are quite a few structural changes that happen, and would be tricky to migrate across later beyond copy-pasting the changes into the new structure.

### Google IO 2014 Update

http://youtu.be/hu4U8XKmJGA