Add rmate command line utility

The rmate command line utility allows you to remotely edit files via an ssh tunnel in TextMate
I don't know that there can be...the purpose of this script is to be run on a remote machine, via an SSH connection, and it tunnels back through on a certain port.

I think that `--help` or `--version` would be your best bet for a test.  Maybe ensure that `rmate --version` returns `rmate version 1.5.7 (2014-02-06)` ?

It *is* just a script - copied as-is...there is no compilation, patching or anything going on.  Perhaps it makes more sense for this to live in homebrew-binary?