Updated locators and navigators for menus and submenus.

Latest Foreman has unique IDs for all menus and submenus now.
Removed a few obsolete tests and updated logout function.

Foreman does not (yet) have a "reset/forgot my password" feature, so
removing unused tests and methods for now. Logout method now uses the
new navigation menus.
PEP8 cleanup (long line and unused imports).
Fixed tests.ui.test_Login.Login.test_successful_login.

The locator used to determin if the user was logged in or not was incorrect.
Merge pull request #84 from omaciel/fixmenus

Foreman nightly has unique IDs for all menus and submenus.