Use of CFFI next to ctypes #304

I'm working on the implementation of Meadowlark's SLM. I'm bringing what I did on Mick's original code to adapt the newer blink dlls. At the time, I pretty much had to adapt everything as the newer blink SDK was pretty different. I did all of that using CFFI and not ctypes. Why I do this is vague in my memory but I remember some things, including the own examples of Meadowlark, not working using ctypes.

In my opinion, CFFI is more convenient than ctypes as soon as you go beyond the classic "hello C world" example. In particular is going to extract of information from the header files, presumably overcoming poor documentation issues.

I'd suggest adding CFFI as a dependency to microscope