soup-session: fix connection-closing behavior on abort

soup_session_abort()'s docs claim that it closes "all idle persistent
connections", but it was actually trying to close *all* connections,
including ones that were being actively used in other threads. Fix
that.

https://bugzilla.redhat.com/show_bug.cgi?id=1093314
Add tls-interaction property to SoupSession

This can be used by applications to do client-side certificates via
the new g_tls_interaction_request_certificate().  Will be used by
OSTree at least.

Also add a test to tls-test.

Based on a patch from Colin Walters.

https://bugzilla.gnome.org/show_bug.cgi?id=334021
Pop the thread default main context not from the callback but from where it was pushed

Based on a patch by Dmitry Shatrov <shatrov@gmail.com>, see
http://mail.gnome.org/archives/libsoup-list/2011-November/msg00000.html

https://bugzilla.gnome.org/show_bug.cgi?id=729737
Updated Brazilian Portuguese translation
Updated Spanish translation
Updated Hebrew translation
Updated Czech translation
docs: ignore soup-socket-private.h

https://bugzilla.gnome.org/show_bug.cgi?id=730779
test-utils: fix some bugs with SOUP_TEST_SERVER_NO_DEFAULT_LISTENER
soup-message-server-io: handle "CONNECT" syntax when parsing requests
soup-server: add soup_client_context_steal_connection()

Add a method to allow a SoupServer handler to steal the connection
from the server, and use this in simple-proxy to implement CONNECT.

Incorporates a patch from Lionel Landwerlin.