Fix error display w/o session.

Fix display of errors w/o a valid session by:
  * wrapping @css[:background_color] into css_background_color,
  * adding rescue to role_allows.
Fix: session[:last_trans_time] was not set.

session[:last_trans_time] is not set in the login request but later.
We need to anticipate this in the PrivilegeCheckerService.
Add tests for referer checking on requests.
Refactor and cleanup validate_user in DashboardController.
Simplify set_user_time_zone.
Simplify ie8_safe_redirect calls.
RBAC: refactor and remove fallback.
Fix small issues in English locales.

Remove spaces at the end of line.
Fix one key.
Fix a typo.
validate_user: fixes and tests.
Fix specs according to Rubocop complaints and review comments.
Fix specs after RBAC refactoring.
ApplicationController: better name for a method.
Split and simplify method validate_user.
Fix dashboard_controller specs after rebase.
Disable Utilization button for Instance if C&U data is not collected

 https://bugzilla.redhat.com/show_bug.cgi?id=1127009
Added support to fleece multiple images.

- Added product feature for image_scan. Added button to scan multiple images to Images list view toolbar and changed Image summary screen toolbar to use correct button id.
- Updated count of product features in spec test

https://bugzilla.redhat.com/show_bug.cgi?id=1141353
https://bugzilla.redhat.com/show_bug.cgi?id=1140853
add appliance_console Prompt#ask_for_string

- can use just_ask, but this is more similar to others
- support net/ssh in prompt specs
- present? not available outside of rails

https://bugzilla.redhat.com/show_bug.cgi?id=1138723
appliance_console#local_database?, #database?

- needed for key generation logic

https://bugzilla.redhat.com/show_bug.cgi?id=1138723
Alias within a method definition AFTER the return is unreachable.
This return is unreachable.