add some more detailed licensing information for TimGM6mb.sf2 (from Debian)

Source/r_things.c

@@ -602,8 +602,8 @@ void R_ProjectSprite (mobj_t* thing)
 
   // get light level
   if (thing->flags & MF_SHADOW)
-    vis->colormap = NULL;               // shadow draw
-  else if (fixedcolormap)
+    vis->mobjflags |= MF_TRANSLUCENT;
+  if (fixedcolormap)
     vis->colormap = fixedcolormap;      // fixed map
   else if (thing->frame & FF_FULLBRIGHT)
     vis->colormap = fullcolormap;       // full bright  // killough 3/20/98

soundfonts/copyright

@@ -0,0 +1,28 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: timgm6mb
+Source: https://github.com/musescore/musescore-old/commit/90c33ef9d87b3f5ff92efd3b07d89eb455fb1fef
+
+Files: TimGM6mb.sf2
+Copyright: 2004 Tim Brechbill <https://www.timbrechbill.com>
+  2010 David Bolton <davidkbolton@gmail.com>
+License: GPL-2
+ This package is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License version 2.
+ .
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>
+ .
+ On Debian systems, the complete text of the GNU General
+ Public License version 2 can be found in "/usr/share/common-licenses/GPL-2".
+Comment:
+ Thomas • Dec 6, 2009 - 16:51
+ Tim came back to me with some more information about the soundfont: "I created
+ some of the samples myself and all others are either public domain or fall
+ under the terms of the GNU General Public License." For me this is enough to
+ add his soundfont to the repository.
+ <https://musescore.org/en/node/1463#comment-9168>