MacGPG2_Updater doesn't have to be a Formula.
Remove falsely added patches.
[NEW] FileDownloadStrategy for Homebrew

- Use a local directory as code repository.
- Also accepts a relative path.
- Caches the code, so it's only re-copied
  if the version changes.
MacGPG2_Updater formula is no longer patched.
Merge branch 'dev' of https://github.com/GPGTools/MacGPG2 into dev