full implement interface

see https://github.com/sebastianbergmann/phpunit-selenium/issues/298
Merge pull request #24 from Slach/fix_Selenium2TestCase_ScreenshotListener

full implement interface
Add active method to session, retrieving active element
Add doc for active method in session
Add active test for active method in session
Fix unit test for active method
Update documentation
Add active session-command class
Use active session-command and re-use response-value method for active element
Remove available since comment
Add active session-command to Autoload
Merge branch 'master' of github.com:sebastianbergmann/phpunit-selenium
Merge pull request #25 from marcelerz/add_active

Add active method to determine active element
Merge branch 'master' of github.com:giorgiosironi/phpunit-selenium
Improving error messages in case of 500 from Selenium.
Repairing Element::value() with never versions of Selenium which removed the GET /value HTTP call from the JSON Wire Protocol
Upgraded versions of Selenium Server and Firefox for tests
Imposing PHPUnit 3.7 for now
Updated test for key events
Local firefoxes may not be running while Selenium starts up other versions