colorbox: Upgraded module from version 7.x-2.2 to version 7.x-2.3.

Important: When updating to this version of the Colorbox module you need to update the Colorbox plugin to v1.3.21.1 or later as well.

Bug fixes:

Updated the README with new download URL.
Updated the Drush command with new download URL and code to rename the directory to colorbox.
colorbox: Upgraded library to version 1.4.1.
New referencing our custom git_deploy repository on Github.
Updated .gitmodules to have the correct remote path for drupal-git_deploy.
MIDD: When setting the project name, remove the 'drupal-' prefix from Middlebury customized modules.