[WIP] Veusz build for Windows

Fixes Veusz to build on Windows. Changes made:

- Adds auxiliary packages `qt-headers` (for the Qt header and .lib files) and `sipconfig` (for sipconfig.py)
- Patches veusz's build script to use the correct include directories

This builds using the "Windows SDK for Windows 7 and .NET 3.5" (7.0) (http://www.microsoft.com/en-us/download/details.aspx?id=3138). Only tested on 32-bit Windows XP/Python 2.7.

Bugs:

- Icons do not show up (still looking into this)