Added deprecation warning for tag name
Add deprecation warnings for class name, tag name locator strategies.

Deprecations warnings will now be thrown for:
* 'tag name' in the native context
* 'class name' in the native context
* 'class name' in the web context

'class_name' is now a valid locator strategy for checkValidLocStrat

Add test for new class name locator
rename createCommand createGetElementCommand
Adding unit tests for new exception throwing
Add test for incorrect UIA class names
Merge pull request #2153 from DylanLacey/class_name_strat

Add class name locator strategy, comply with MJSONWP