Log user's IP address in login auditing

[jeremydmiller]

From a conversation on the user list w/ Peter Wentzel: https://groups.google.com/forum/?fromgroups=#!topic/fubumvc-devel/43BZc0FGDJQ

[pdwetz]

Probably best to utilize X-Forwarded-For http header, as it's cluster/proxy aware. Worth noting it can return multiple IP's, but the first should be the client's address.

http://en.wikipedia.org/wiki/X-Forwarded-For