Fix r_mergeLightmaps 0 crashing OpenGL2 renderer

tr.fatLightmapStep was 0 and caused modulus division by 0.
Merge remote-tracking branch 'ioquake3/master'
Prevent the skip of the glyph if it does not fit
Merge pull request #5 from morturp/patch-1

Prevent the skip of the glyph if it does not fit
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	code/renderercommon/tr_font.c