Added key to Provider class
Added validate method to Provider
Replaced old selenium calls

As element() and elements() now take root arguments, all calls within
web_ui no longer need to use direct calls to find_elements_by_xpath and
can now instead use the functionality of element() and its counterpart instead.
cfme.web_ui.tabstrip

Element common in Configure / Configuration and possibly on other places.
Fixed unoptimized arg names in selects
Merge pull request #360 from psav/fix_selects

Fixed unoptimized arg names in selects
Merge pull request #357 from psav/replace_xpath_calls

Replaced old selenium calls
Merge pull request #354 from mfalesni/newmodels

cfme.web_ui.tabstrip
Merge pull request #353 from psav/fix_cloud_prov_tests

Added validate method to Provider
Added select() function

Added select() to allow user to specify the select type (value/text) as
a tuple and then act accordingly.
Merge pull request #361 from psav/add_select

Added select() function
Fixed stale element when re-using trees
Merge pull request #362 from psav/fix_stale_chloroplast

Fixed stale element when re-using trees
Change cfme.Credential to use getattribute
Use singledispatch for finding sel elements
Use singledispatch to fill forms
Atomic update to provider module
* Use fill generic function to fill forms
* Remove inner classes for Provider details
* refactor update() logic
* refactor discover() logic
Fix uncaught selenium errors and typo