fixed bug with resond_to after adding method_missing
fixed bug with resond_to after adding method_missing

- initialize_this relied on respond_to? for strategy
  that is no longer valid that we have respond_to_missing?
- change to check for actual object. This constraints us to
  implement Hash, Watir and PageObject rather than objects
  that merely respond to those messages.

rubytester/domkey,rubytester/domkey