GTask pushed

[Dan Winship <danw gnome org>]

I've pushed the GTask code to glib master.

For those who weren't watching the bug, this is a replacement for
GSimpleAsyncResult and GIOScheduler with some additional functionality
and simplifications. The docs
(http://git.gnome.org/browse/glib/tree/gio/gtask.c#n28) cover the use
cases in detail and give sample code, as well as hints for porting from
GSimpleAsyncResult.

Parts of gio have been ported from GSimpleAsyncResult to GTask now.
(Mostly the networking-related parts, because those are the easiest for
me to test.) The wip/task branch in git has not-heavily-tested ports of
the rest of gio, which I will eventually land later on in the cycle if
other maintainer-types don't do it first. I don't think we decided if
we're actually going to formally deprecate GSimpleAsyncResult in 2.36 or
not.

The API is not really expected to change (though it may be extended),
but if you see things you think are problematic, bring them up sooner
rather than later.

-- Dan