New methods
- #header_mappings_dir: specifies the folder from which to preserve the name-spacing
- #exclude_headers: specifies the headers that should be excluded by the header mappings.

Currently those methods are used by RestKit and SSZipArchive.

- #add_libraries
- #add_frameworks

* master:
  Minor copy change
  A few small fixes related to integrating multiple targets/projects.
  Add rake ~> 0.9.0 (for rake/file_list.rb file) to gemspec. Closes #195.
  Fix for https://github.com/CocoaPods/CocoaPods/issues/141
  [Push] Bypass pre-commit hook.
  [Fix] GitHub downloader was downloading the repos twice.

Conflicts:
	spec/unit/resolver_spec.rb

Fixed external subspec dependency

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