Add instance numbers to page output on Android
Add instance numbers to page output on Android

Example:

android.widget.TextView (7)
  text, desc: NFC
  id: android:id/text1

find_element(:uiautomator, 'new UiSelector().className("android.widget.TextView").instance(7)').text # NFC

Fix #214

dav/ruby_lib,VinceBarresi/ruby_lib,KazuCocoa/ruby_lib,SrinivasanTarget/ruby_lib,justin808/ruby_lib