ANDROID: Implement auto-rotate support

[scarmonag]

Currently the port is always in landscape mode, and when some games require keyboard input (like older Sierra AGI games) the keyboard uses more than 50% of the screen, covering the games.
If auto-rotation with resizing of the the game screen is implemented, it will be the user's choice to have the game displayed in full screen landscape for non-keyboard-requiring games or scaled down on top of the portrait view and pull the native Android keyboard (or even better, a ScummVM variant with F keys).
All they would have to do is turn their device as they already do for a lot of other apps where the layout changes with rotation.

Currently when the device is put in portrait mode, nothing happens, the image is still landscape so the user has no alternative but to turn the device.
I think it would improve the port a lot if the users had a choice for display.

Thank you,