Fixes #3753 - always use main_app to determine paths for running an isolated namespace plugin

fixes #3790 - Added support for isolated engine to foreman menu

Fixes #3838: Adds ability to define a divider when declaring a menu item
from a plugin.

fixes #3491 - API v2 rabl templates base, main, show for each controller

i18n - extracting new, updating rails, pulling from tx

fixes #2600 - fixed gettext extraction on vms forms

fixes #3832 - foreman supplies user for GCE images, fog expects username

fixes #3820 - adds exception output to menu item authorization check

fixes #3822 - updated Rackspace datacenter list

fixes #2983 - Add autosign#index to API v1 and v2 and remove from UI controller