First attempt on libsoup new-io with caching capabilities

[Sergio Villar Senin <svillar igalia com>]

Hi all,

I have been working these last weeks in adding caching support for HTTP
to libsoup. As Dan Winship suggested me, I started taking a look to the
new-io branch that is supposed to be the starting point of a future
libsoup "streamed" version. See
https://bugzilla.gnome.org/show_bug.cgi?id=557777

I rebased the new-io branch against current master and managed to get
async methods working. After some more work sync methods work now as
well although not as reliably as it should. You can test both in get.c
test for example.

Finally last week I took a look at Xan Lopez's original implementation
for soupcache (https://bugzilla.gnome.org/show_bug.cgi?id=523100) and
started to work on it trying to move it to the new libsoup-io API.

I have a working version of that currently uploaded to gitorious
http://gitorious.org/libsoup-io-cache/libsoup-io-cache. So if anybody is
in the mood for reviewing it and give me some feedback that would be great.

Br