cleaning up my act

I hadn't touched the fundamentals of this in almost a year and it was rather untidy. Derelict vim automations in the Makefile, obsolete functions, lack of organization in the source files, etc. It was bothering me so I fixed it.

I took the time also to crack down on frivolous #includes and add some fancy attributes. Hopefully the code is more compiler-friendly now. Noticeably absent is ((always_inline)) which I couldn't be bothered to figure out how to make work across compilation units while at the same time respecting the 42 Norm so, whatever, hope gcc does just-in-time inlining or something.

Speeding up ft_memcpy with a chunking optimization had been on my list of things to do for a while as well. I think the way I did it is legit with no side-effects, although not very sophisticated. Low-hanging fruit update but major speedup.

Reminder: this project is eternally in pre-release. Don't use it. I'm not that good.