Added a test for it so we dont flood the logs (r1523)

GError: This build of gdk-pixbuf does not support saving the image format: ico

But we should either save it in png format (and hope the user's version of windows supports that or at least fails gracefully) or find a library that will convert it to ico (not found so far - only reading is supported, see PIL, etc)

Maybe pywin32 can give us access to something in windows API that will do the job, ​this is not too far off (it's only reading though).

Found ​Icon.Save in .NET

​this example writes it out straight to file. Newer versions of windows support icons as PNGs, we should at least do that when saving .ICO fails.

Our app avoids placing an icon in the task bar (window.SKIP_TASKBAR), so windows should get out of the way and let us live in the tray (aka notification area). But no, nanny-microsoft decides they know best, so we would need some code to go and hack the registry (yuk), something like what is mentioned in ​this thread.

It kinda builds against gtk-osx with tweaks, but fails at runtime with:

ImportError: dlopen(/Library/Python/2.5/site-packages/wimpiggy/lowlevel/bindings.so, 2): Symbol not found: _gdk_x11_atom_to_xatom_for_display

No idea if gdk on osx implements get_xatom...