Clarify public domain statement similar to qt-faststart.c.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9574 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

cws2fws.c

 /*
  * cws2fws by Alex Beregszaszi
- * Public domain.
+ * This file is placed in the public domain.
+ * Use the program however you see fit.
  *
  * This utility converts compressed Macromedia Flash files to uncompressed ones.
  */