Merge commit 'remotes/github/master'

* commit 'remotes/github/master':
  Piston::Git::Commit#validate! implementation.
  Piston::Svn::Revision can validate itself.
  Default recalled values are an empty Hash now.
  Piston::Svn::Repository#at with recalled values passes the recalled 
  values to Piston::Svn::Revision#new.
  Some tests for Piston::WorkingCopy #exist?, #pistonized? and #validate!
  Depend on ActiveSupport.
  Removed dead Piston::Commands::Import#constantize.
  Refactored Piston::Commands::Base to automatically call #validate! on 
  the returned working copy.
  Rewrote how the LockUnlock command reports it's work.
  Implemented Piston::WorkingCopy#validate! to raise an exception unless 
  everything is OK.
  Refactored the working copy guessing into 
  Piston::Commands::Base#guess_wc.
  If the Turn gem is available use it, else not.
  Made the info command much simpler: simply output the #to_yaml version 
  of the recalled values.
  The CLI is responsible for putting the text on STDOUT, not the info 
  command.
  Renamed #lock_unlock_command to #info_command in test/unit/test_info.rb
  WorkCopy.info tests.
  Fixing the default lock.
  Adding info in git repository.

Conflicts:

  Manifest.txt