Pass background colour as a parameter to draw_gts and draw_adjs, so

Pass background colour as a parameter to draw_gts and draw_adjs, so
that we can pass -1 in calls from game_print(). Fixes a printing bug
in which all the adjs and gts were overlaid with giant black
rectangles! (Because COL_BACKGROUND doesn't mean the same thing in
that context.)

[originally from svn r9175]