Megapixels 2.0 alpha release

It's been quite a while since I wrote a Megapixels update post. Since my last post libmegapixels has had a lot more testing on hardware other than the PINE64 devices and the Librem 5 which I originally wrote it for. This obviously found a few flaws in my library code for edge cases I hadn't had to deal with before but overall the fundamental ideas behind the library seem to work. I have now removed the last device-specific workaround from the libmegapixels code and the device support is now purely config fi