initialise canvas to empty list to avoid pickling errors on backend init failures (needs to be iterable)
adjusted fallback warning sequence
warning instead of crash if video_capabilities do not support resumed mode
reorganised backend initialisation
restructured mode_data
corrected automatic mono monitor selection
--composite, --mono --> --monitor=composite, --monitor=mono, --mono-tint
config - fixed passing of empty strings where empty list should be
warn if mounts don't work
renamed num_colours --> num_attr
renamed num_palette --> num_colour_choices
brought some sanity into palette system
relocated palette functions; docstrings