update real device info
Merge pull request #2204 from jlipps/real-xpath

Real XML-based XPath for iOS
add test for existing xml source behavior
update android xml source to have class names as node names rather than just 'node'
deprecate use of json page source
add real xpath support for android
- relies on xpath support for ios pull request
- adds support under the '-real xpath' locator strategy
- deprecates the original xpath strategy, which will be replaced in 1.0
- because we have no way to get a dom fragment starting from an element,
  this strategy will only work for root-level queries