update shaderlab license

licenses/shaderlab

@@ -1,7 +1,11 @@
-  Usage and redistribution policy: Textures may be freely downloaded, modified,
-  and used in free maps, mods or total conversions provided this copyright
-  notice is left intact and a link to Shaderlab is provided in the credits or
-  read-me file. Other non-commercial applications are considered on a
-  case-by-case basis via e-mail. All other usage requires written permission.
-  Bulk redistribution or archival of the textures in any medium, digital or
+All shaderlab (http://www.shaderlab.com/) textures (by Randy 'ydnar' Reddig)
+are subject to the following license:
+
+  Usage and redistribution policy: Textures may be freely downloaded,
+  modified, and used in free maps, mods or total conversions provided
+  this copyright notice is left intact and a link to Shaderlab is
+  provided in the credits or read-me file. Other non-commercial
+  applications are considered on a case-by-case basis via e-mail.
+  All other usage requires written permission. Bulk redistribution
+  or archival of the textures in any medium, digital or
   otherwise (except mapping packages for mods) is prohibited.