Removes unversioned files from perforce repository. Script is in beta, though it works. It will be undergoing changes to add thread support to see how much we can speed up searching; depends a lot on your storage device. I will then also try seeing if I can reduce the calls to fstat a bit, it will be a bit more complicated.
This script does parse __.p4ignore__ ignore files, compiles the fields as regex, and scans every directory and file against the local and parent __.p4ignore__ files. This is my first time doing something like this, and I just realized this isn't actually correct; I need to update how things are ignored to follow the [spec](http://www.perforce.com/perforce/r12.1/manuals/cmdref/env.P4IGNORE.html), since it's not straight up regex.
