[sugar] sugar.graphics cleanup

[Marco Pesenti Gritti]

The move to gtk is pretty much completed. There a few leftovers of the 
old graphics approach which we need to cleanup while we go. I won't have 
time to do it all in one time, so I thought I'd post this as reference.

color.py
font.py

Merge the useful bits of those in the style.py I'm working on.

frame.py

I think we can just drop this one.

iconbutton.py

Drop once we port the frame to use gtk widgets.

units.py

We are going to specific all units in pixels. Drop once the conversion 
is completed.

roundbox.py

Should probably keep given the obsession of our designer for round boxes 
;) Rename to canvasroundbox.

spreadlayout.py

Unsure, might be better to keep it private.

animator.py
canvasentry.py
canvasicon.py
combobox.py
icon.py
__init__.py
menuitem.py
notebook.py
objectchooser.py
palettegroup.py
palette.py
panel.py
radiotoolbutton.py
toggletoolbutton.py
toolbox.py
toolbutton.py
toolcombobox.py
window.py
xocolor.py

All of these will stay.

Marco