Add back button for Android
Add text contains

Fix #301
Merge pull request #309 from bootstraponline/android_back

Add back button for Android
Add * XPath unit test
Move to adb.js
Merge pull request #308 from bootstraponline/text_contains

Add text contains
Merge pull request #314 from bootstraponline/adb_cmd

Move keyevent to adb.js
Skip uninstall on fastReset
Merge pull request #312 from bootstraponline/skip_on_reset

Skip uninstall on fastReset