Support for new selenium-server versions

• added support for selenium-server-standalonver > v2.31.0
• improved command executions for click, waitFor and getLocation
• removed duplicate command setSize()
• added more tests
• removed selenium-server-standalonver jar from repository
• implemented install script for downloading this jar into .bin folder
• cleaned up git repository (got rid of big jar files in git history) - requires to re-checkout this repository