Brings WaitExpression to a working state under webdriver.  This triggered some minor changes to the selenium implementation to keep things in line.  Most significantly a change in the behaviour of evaluate_element.  I've attempted to maintain backward compatibility to the old behaviour for the selenium implementation.
fix missing jquery
friendlier domain for example tests
Merge pull request #4 from drd/feature/waitexpr

Brings WaitExpression to a working state under webdriver.