updated android_uiautomator selector tests to use ByAndroidUiAutomator method
added UiScrollable support to -android uiautomator locator strategy
deprecated 'dynamic' locator strategy. fixed strategy deprecation code.
Merge pull request #2807 from Jonahss/uiautomatorSelectorUpdate

Uiautomator selector update, fixes #2264
test fix
alert test fix
Merge pull request #2836 from sebv/alert-fix

alert test fix
Improve find by id on Android

The old code used exists() which is expensive because we're finding
the element more than once.
Merge pull request #2834 from bootstraponline/fix_id

Improve find by id on Android
fix android webview tests