code refactoring. Moved subscribe_all and unsubscribe_all to tasks
firstboot functons a little differently in RHEL6 and had to add this to check back button behaviour during register
firstboot back button functions differently after register. Incorporated changes for that and improved test to check back button
improved tests to function with RHEL6 and added more cases to check_escape_button
added the changed UI locator for proxy-button in firstboot
made a small change to existing code for the test to work efficiently