Merge pull request #1321 from samaitra/master

Fixed bootstrap build error to download dependencies
Ensure APK is signed
Merge pull request #1323 from bootstraponline/master

Ensure APK is signed
Add new command to press on the Home button for Android.


The Android UiDevice has method to press the Home button. To support this a new mobile command is added 'home'.

For Java binding, the client code will be...

((JavascriptExecutor)driver).executeScript("mobile: home");
Merge remote-tracking branch 'upstream/master'