Added public domain license text

stb_rect_pack.h

@@ -36,6 +36,12 @@
 //     0.05:  added STBRP_ASSERT to allow replacing assert
 //     0.04:  fixed minor bug in STBRP_LARGE_RECTS support
 //     0.01:  initial release
+//
+// LICENSE
+//
+//   This software is in the public domain. Where that dedication is not
+//   recognized, you are granted a perpetual, irrevocable license to copy,
+//   distribute, and modify this file as you see fit.
 
 //////////////////////////////////////////////////////////////////////////////
 //