darcs patch: Added Data.Map.insertWith'

Tue Sep 5 13:11:49 CDT 2006 John Goerzen * Added Data.Map.insertWith' Use of insertWith can lead to memory leaks. This function was suggested by Udo Stenzel at http://article.gmane.org/gmane.comp.lang.haskell.cafe/14864 This type of algorithm solved a real problem discussed in this thread: http://thread.gmane.org/gmane.comp.lang.haskell.cafe/14852