expand_object: Remove register exchanges by renaming registers.
Update TODOs.
set_morale_flag_screen_attributes: Document A as an input parameter.
sub_B916: Swap LDIR for memset.
sub_E3FA -> flip_24_masked_pixels, sub_E40F -> flip_16_masked_pixels.
mask_against_tile: Remove register exchanges by renaming registers.
called_from_main_loop_8: Reduce.
Use address and integer sanitisers (clang).
Extract font.
wave_morale_flag: Replace gotos with if/else. Fix $A061 interpretation of BIT 1.