Add Settings api, and xpathCompression setting for Android

Same as last, time, you need to use my fork of wd.js to run the tests...
There's some [restart logic here](https://github.com/appium/appium/blob/9a62e7ba7da90ccaaa492b91088d85959291f93f/lib/devices/android/android.js#L158). I'm not sure where else uiautomator is restarted.