0.15.0

[Config] Support extension for Podfile.

* master:
  [Specs] Minor fix for Command::Push.
  [Push] Use git! where possible.
  [Specs] fix for the fix that was supposed to fix Travis.
  [Specs] Fix for Travis issues.
  [Source] The name should be an attribute.
  [Specs] Fixed Travis errors related to Command::Repo.
  [Linter] Fixed minor bug.
  Update CHANGELOG.md
  Update lib/cocoapods/generator/acknowledgements/markdown.rb
  Update lib/cocoapods/generator/acknowledgements/markdown.rb
  [Linter] Promote long summary warning to an error.

Conflicts:
	lib/cocoapods/command/push.rb

Forcing UTF-8 encoding on licenses generation. Fixes #530

Update CHANGELOG for #530

Forcing UTF-8 encoding on licenses generation in Ruby 1.9 only. Fixes #530

Forcing UTF-8 encoding on licenses generation. Fixes #530

* master:
  [Specs] Fix repo specs.

* master:
  [Repo] Use raising bang variant for git operations.

* master:
  [Repo] Use raising bang variant for git operations.
  [Source] Allow the specify the master repo dir from an environment variable.
  [Linter] Improved checks for the summary and the git tag.
  [Repo] Fix banner.
  [Source] list the name of the repos.
  [Changelog]
  [Config] Added update_notification attribute.
  Support extracting .tar.bz2 files

The variable is `CP_MASTER_REPO_DIR` and potentially paves the way for
supporting a deeper linting of CocoaPods/Specs. Every check would be
supported, including checking that the files patterns match, except
xcodebuild checks.

Support extracting .tar.bz2 files