hplip: start work on making python programs work
hplip: now hp-setup actually shows a dialog
enable networking support for hplip, net_snmp is available now
hplip: make pyqt4 dependency conditional on qtSupport
Merge branch 'hplip' of https://github.com/aristidb/nixpkgs

From aristid:
The hplip package wasn't really "python-aware" before. It should be now: I tried running hp-setup, and it works.
I've also enabled network support now.