Merge branch 'climbingshit2_electricboogaloo' into 'master'

Climbing shit 2 electric boogaloo: an adventure in how much toast hates how the ogl renderer was implemented

Fixed Knuckles being able to climb in space in OpenGL.

Using the last-touched line instead of R_IsPointInSubsector because FLOAT_TO_FIXED is bad in P_ functions

To understand the original problem: look at AjustSegs(void) in hw_bsp.c. It reallocates the vetex_t pointers for lines as POLYVERTEX_T pointers, and of COURSE things are gonna get wacky when you're casting pointers.

This merge request is into master because it's a bug that's IN master and must never reach the public because of how bad it is

See merge request !101