* master:
  [Installer] Don't generate documenation if already installed
  [Command::Spec::Linter] Fix - Skip documentation generation
  [Config#doc] Renamed to generate_docs
  [Command::Spec::Linter] Bug fix.
  [# 242 Command::Spec::Linter] Refactoring
  [#246 | Resolver] Validate plaforms against each target.
  [Resolver] Check target plafroms instead of podfile.

Conflicts:
	lib/cocoapods/resolver.rb