Android client suggestions

[pspillai]

A few suggestions on improving the Android client.

1. Have it query the server to find which style models are available. This will allow the server to be updated with new models independently of the client.
2. The display aspect ratio is sometimes far different from the images -- allow an option to scale preserving the pixel ratio in addition to filing the screen.
3. Add button to switch between front and rear camera while viewing (not just in the set up).
4. Add button to save an image while viewing.

[teiszler]

For 2, we now have a predefined set of resolutions which can be selected from in the Experimental settings section. We should try to compute a list of possible resolutions based upon those available on the device which would maintain the aspect ratio.

Addressed 4 in the upcoming release which corresponds to this commit.

Looking at using the Gabriel control mechanism to address 1.

[jaharkes]

I think at this point 1, 3 and 4 have been addressed.