Summary:
This moves the native setup to a separate gradle file and unpacks everything outside the build folder. That way we don't throw everything away on every incremental build.
This is an intermediate step to get to a more declarative setup like Fresco has it and get rid of the individual hacks we have for every download.
Pull Request resolved: https://github.com/facebook/Sonar/pull/154
Reviewed By: jknoxville
Differential Revision: D8833812
Pulled By: passy
fbshipit-source-id: 2424c9d6e22e6092c04af344e06939b4a6aba041
