pidgin/pidgin

Add icon-name, icon-search-path, and icon-resource-path to PurpleProtocol

These are now used by pidgin_create_icon_from_protocol which will attempt to
load the icon for the protocol from the default GtkIconTheme if the protocol
has a non NULL value for icon-name.

pidgin_ui_init was also updated to add icon-search-path and icon-resource-path
to the default GtkIconTheme when a protocol is registered. It also scans all of
the protocols that have been already been registered as that happens before the
ui is initialized.

Testing Done:
Removed old local icon and then ran with an inverted icon to make sure pidgin was displaying the icon from the resource.

Reviewed at https://reviews.imfreedom.org/r/790/
Björn Voigt <bjoernv@arcor.de> Björn Voigt <bjoern@cs.tu-berlin.de>
Björn Voigt <bjoernv@arcor.de> Bjoern Voigt <bjoern@cs.tu-berlin.de>
David Woodhouse <dwmw2@infradead.org> <David.Woodhouse@intel.com>
David Woodhouse <dwmw2@infradead.org> <dwmw@amazon.co.uk>
David Woodhouse <dwmw2@infradead.org> dwmw2 <dwmw2@infradead.org>
# not sure how to make this one work because this doesn't do it..
dequis <dx@dxzone.com.ar> dequis <dx@dxzone.com.ar
dequis <dx@dxzone.com.ar> dx <dx@dxzone.com.ar>
Eion Robb <eion@robbmob.com> Eion Robb <eionrobb@gmail.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com> Elliott Sales de Andrade <qulogic@pidgin.im>
Elliott Sales de Andrade <quantum.analyst@gmail.com> Elliott S <quantum.analyst@gmail.com>
Ethan Blanton <elb@pidgin.im> Ethan Blanton <elb@fiji-systems.com>
Ethan Blanton <elb@pidgin.im> Ethan Blanton <elb@kb8ojh.net>
Gary Kramlich <grim@reaperworld.com> <grim@pidgin.im>
Jerin Philip <monu1618@gmail.com> Jerin Philip <jerin.philip@students.iiit.ac.in>
Jonathan Champ <jrchamp@ncsu.edu> Jonathan Champ <royanee@users.sourceforge.net>
Jorge Villaseñor <salinasv@pidgin.im> Jorge Villaseñor <masca@cpw.pidgin.im>
Mark Doliner <mark@kingant.net> Mark Doliner <markdoliner@pidgin.im>
Matěj Cepl <mcepl@cepl.eu> Matěj Cepl <mcepl@redhat.com>
Michael McConville <mmcconville@mykolab.com> Michael McConville <mmcco@mykolab.com>
Michael McConville <mmcconville@mykolab.com> mmcconville@mykolab.com
Mike Ruprecht <cmaiku@gmail.com> Michael Ruprecht <maiku@pidgin.im>
Richard Laager <rlaager@wiktel.com> Richard Laager <rlaager@pidgin.im>
Robert Vehse <robertvehse@fastmail.fm> Robbie <robertvehse@fastmail.fm>
Shalom Craimer <scraimer@gmail.com> Shalom Craimer <s.transifex2015@craimer.org>
Tomasz Wasilczyk <twasilczyk@pidgin.im> Tomasz Wasilczyk <tomkiewicz@cpw.pidgin.im>
Yngve Spjeld Landro <l10n@landro.net> Yngve Spjeld Landro <nynorsk@strilen.net>