Create openasi project

[bgottula]

I recently wrote some custom libusb code in the capture program to replace some problematic code in the official ZWO driver for video streaming. This worked great, but now there is effectively driver code intermingled with application code. I think it could be cleaner to move this libusb code into a separate project which I'm calling openasi. This would aspire to eventually be a fully open-source implementation of the ZWO camera driver, but to get started only a couple of the APIs would have open-source implementations and the rest would just call into the official driver. Over time the other APIs could be incrementally replaced with open-source implementations until eventually the official driver is no longer needed at all.