Depends: clone qextserialport into our own repository

We need to patch qextserialport to allow 1Mbps communication used with our arduino hardware.

git clone  https://code.google.com/p/qextserialport/

commit 3be3fbf31edf6c91c7838f585b77acd787811296
Author: Nate Weibley <nate.weibley@prioria.com>
Date:   Mon Jul 8 16:33:41 2013 -0400
qextserialport: allow to use more baudrates under Windows

This patch just works pretty fine with our Arduino 1Mbps setup (FTDI UART-USB)
Depends: import rtmidi 2.0.1 from archive