Cleanup: remove redundant, invalid info from headers

BF-admins agree to remove header information that isn't useful,
to reduce noise.

- BEGIN/END license blocks

  Developers should add non license comments as separate comment blocks.
  No need for separator text.

- Contributors

  This is often invalid, outdated or misleading
  especially when splitting files.

  It's more useful to git-blame to find out who has developed the code.

See P901 for script to perform these edits.

source/gameengine/Expressions/intern/StringValue.cpp

@@ -12,7 +12,6 @@
  * in supporting documentation.  Erwin Coumans makes no
  * representations about the suitability of this software for any
  * purpose.  It is provided "as is" without express or implied warranty.
- *
  */
 
 #include "EXP_StringValue.h"