From ae3720d2001c2d6b70a9759ec46fb4233aca6812 Mon Sep 17 00:00:00 2001
From: Mark Rushakoff
Generate a globally-unique id for client-side models or DOM elements
that need one. If prefix is passed, the id will be appended to it.
+ Without prefix, returns an integer.
_.uniqueId('contact_');