Add ability to take stills

[catdogmat]

It would be awesome if you could take still photos with this camera. Please consider adding a button for photos and possibly settings for shutter speed and iso.

[schoolpost]

Yes, taking still frames as .DNG file is possible; but is not fully implemented in the cinepi framework yet.

[mrjohnc]

Adding this function might help encourage more people to take part in the project, there are a large number of open source people interested in photography and open source cameras