Shell header template

Automatically populate filename, creation date and modification date in
shell header.  Also add the ability to update header on old scripts

.vim/templates/sh

@@ -2,7 +2,7 @@
 #!/usr/bin/env bash
 #===============================================================================
 #
-#          FILE: 
+#          FILE: filename
 #         USAGE:  
 #   DESCRIPTION: 
 #         NOTES: