Dar 2415

Selenium tests refactored for new modals. Ticket:
https://wikia-inc.atlassian.net/browse/DAR-2459


assured tests:
ForumEditModeTests
MessageWallTests
ForumThreadTests
ForumBoardTests

1. Selectors for new modals added
2. close FAQ modal method improved
3. removed duplicate Thread Tests (remove and close)