Get the cache for testing.

* master:
  Enable caching for specs and remove configurable git cache size.
  Save Git chaches in ~/Library/Caches/CocoaPods/Git.
  [Downloader::Git] Skip cache pull if ref is available.
  Restored Pod::Downloader::Git::GitHub.
  [Git] Fix for Travis errors.
  [Git] Increased default cache to 500Mb.
  [Downloader::Git] Completed cache support
  [Git<<Downloader] Fix for url hash
  [Downloader::Git] Cache repos

[Downloader::Git] Cache repos

Closes #105, #121, #215.

Still need to do it at the target level too.

* master:
  [Command::Spec::Linter] fix for #podspec_warnings.
  [Command::Spec] Template layout fix.
  [Platform] Removed options accessor.
  [Executable] Made executed command more prominent.
  Spelling correctioSpelling correctionn
  [Resolver] Support for deployment target check.
  [Specification#deployment_target=] Switch to Pod::Version
  [Platform#==] Check for deployment target.
  [Platform] Simplify deployment target specification.
  [#212] Check for deployment target

[#212] Check for deployment target