2.2 Backports - add ceil slope double step-up/down and fix sprite/models all black in sector with light level of 256

from STJr/SRB2!840 (0d92bf3d) and STJr/SRB2!840 (diffs) Adds part of P_TryMove code from 2.2 to make ceiling slope collision better and let use sector effect 13 (double step-up/down) on ceiling slopes Also adds pieces (sprites/models lightlevel) from 2.2 opengl sprite/model rendering to avoid sprites/models fully black when inside a sector that light level is 256