Adding test for more thorough testing of `getAttribute` method.
Move `OPTION` element selection checking to JavascriptDriverTest.
Moving extracted test (for element selected state check) back to GeneralDriverTest, but keep as a separate test with try/catch inside.
Also check, that `selected` state is properly reported for multiselects.
Merge pull request #398 from aik099/improved-get-attribute-testing-feat

New test to verify correct work of `getAttribute` method
Merge pull request #396 from aik099/testMultiselect-fix

Move `OPTION` element selection checking to JavascriptDriverTest