Fixes #3 (Make lxml lib optional)
http://code.google.com/p/gae-simpleauth/issues/detail?id=3

Merged from http://code.google.com/r/terencehonles-gae-simpleauth/source/detail?r=48ff28a7321f9b77eeed8871b9dafc581418f927
Thanks Terence!
CONTRIBUTORS section
Bump version to 0.1.4