by ojohansson: Added support to switch environment from outside the site.
by ojohansson: White space cleanup.
Issue #1866664 by AdamGerthel: Added Drush integration.
Issue #1499462 by AdamGerthel: Fixed faulty grammar in messages
by ojohansson: Fixed the name of the last batch process callback.
Issue #1590136 by itaine: Clear the cache after switching environments.