] add SpinnakerGUI
On first run the GUI will use default window size and location values, but on close, will save layout state to an
imgui.ini settings file in the current working directory that will used if present in the working directory of future sessions.
Videos are encoded in H.264, with lossless compression by default, and saved in the current working directory. Different compression rates (see ffmpeg crf) can be set by setting the
compression at start: