Remove editor UI references to hostage faces code

This fixes a build break from 63c77101d3c1c5501c2cb3f0aa7fee1000ed4d83.
Change type of visited[] from char to unsigned char to match D2X
Move declaration of render_mine to render.h
Fix wrong length passed to PHYSFSX_fgets
Fix ancient bug that read Segments[-2].verts during endlevel sequence
Fix automap save bug in large levels
Fix bug that last object is skipped when caching OGL textures
Remove unused 2d/scale.c
Remove unused include/checker.h
Remove unused include/d1x.xpm
Remove unused include/i86.h
Remove unused include/descent.xpm
Remove unused editor/macro.c
Remove various unused misc files