Add support for setting the reply-to header when sending email.
Add support for setting the reply-to header when sending email.

Patch contributed by Thomas Gibson-Robinson. Thanks very much!

Fixes Issue #108


git-svn-id: 7c59d995a3d63779dc3f8cdf6830411bfeeaa67b@83 d4307497-c249-0410-99bd-594fbd7e173e

clones/google-app-engine-django,wtanaka/google-app-engine-helper-for-django