sprout-osx-apps::android_sdk recipe is now fully automated
Added recipe for maven
Update android_sdk recipe:

- Install version 19 build tools, version 18 and 19 platforms
- Put a bash_it script in place to set ANDROID_HOME
Refactor how we download SDK packages. Fixes the problem where multiple
license challenges cause downloads to fail.
Update Android SDK recipe; just install SDK 19 and fix the package number for the Atom image
Update android sdk recipe to use newest build tools, and also install
the support jar and the support repository, which are necessary for
Robolectric / Gradle projects