Fix occasional build issues, which turned out to be improper use of multiple targets
Update links to point to current URLs for resources
Improve formatting where applicable
Switch to recursively scanning for assembly files, as this has proven to scale better
In theory, `src/` could be moved, but that can be done using `make -f path/to/Makefile`
instead, so getting rid of some complexity is worth it.
Also, I doubt there is a use case for this :P
I failed to reinstate this after removing the 0.3.7 RGBFIX workaround. This also means that RGBFIX before 0.3.6 (which introduced `-f`) can be used again.
If compiling with more than one task running at once,
there could be a concurrency on $(DEPSDIR)/tmp.d
Fixed that by making the temporary name unique using the target's name.
