Added getSelect to WebDriverElement

This PR includes the following changes -
1. `getSelect()` is ported from  CandyBean 1.1.3 to CandyBean 2.0.
2. A system test is added for `getSelect()`
3. Some system tests (doubleClick, dragNDrop, getAttribute, pauseUntilVisibleTest, isDisplay) are fixed and passing.
Although you're now accepting the index as an argument, you're not actually using it to determine which selector to return.  Please update this to use the index to find a specific selector in a manner similar to how getElement does it.