2.0 ~> 2.1 Migrator

This migrator:

1. Creates local copies of necessary repositories
2. Copies the appropriate files and directories (including `.git`) from the current directory to the new clone
3. Removes the local Octopress installation and replaces it with the new clone and modified files
4. Moves the new clone with the modified files to the location of the old Octopress installation

This should ensure the migration of the current Octopress installation to v2.1.