Store the configuration file in the XDG configuration directory
Fair enough, not significantly better that way. I'll merge as-is.
Add coverage for display_write_if_dirty_timex
Add missing branch coverage for compare_and_merge_rectangles
Use libspectrum_new0 in libspectrum_tape_block_alloc
Add snap DivIDE, SpecDrum, Fuller Box, and Multiface tests (100-103)
Use libspectrum_new0 in libspectrum_ide_alloc
Use libspectrum_new0 in libspectrum_microdrive_alloc