Create SPOS.h

Header file containing usable functions (so far, only a handful of functions that are theoretically going to be used soon with simple geometry) -- still defining the fundamental code that's needed for the engine to function with input. lotsa horrible snippets of ADHD code and un-optimizations.
c++ really makes me contemplate how horrible I actually am at computers.
I'll post an example main.cpp for testing later.
Maybe have a programming flowchart on what to focus on at each given time?