pidgin/pidgin

Replace the account-actions-changed signal with an actions-changed signal on PurpleProtocolActions

We also propagate the PurpleProtocolActions::actions-changed signal from the
PurpleProtocolManager::account-actions-changed signal if the protocol implements
the PurpleProtocolActions interface.

Testing Done:
Build the docs and ran the unit tests.

I also put a temporary action in the demo protocol plugin and called `purple_protocol_actions_changed` after the demo protocol connected. I will have another pull request that makes this a permenent action, but I want to convert the demo protocol plugin to subclass PurpleConnection before doing so as that will be accounting of everything *much* easier.

Reviewed at https://reviews.imfreedom.org/r/2168/
/*
* pidgin
*
* Purple is the legal property of its developers, whose names are too numerous
* to list here. Please refer to the COPYRIGHT file distributed with this
* source distribution.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, it can be viewed online at
* https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
*/
#ifndef PIDGIN_PIDGIN_H
#define PIDGIN_PIDGIN_H
#include <glib.h>
#ifndef __GI_SCANNER__
# ifdef PIDGIN_COMPILATION
# error "pidgin source files should not be including pidgin.h"
# endif /* PIDGIN_COMPILATION */
#endif /* __GI_SCANNER__ */
#ifndef PIDGIN_GLOBAL_HEADER_INSIDE
# define PIDGIN_GLOBAL_HEADER_INSIDE
#endif /* PIDGIN_GLOBAL_HEADER_INSIDE */
@PIDGIN_H_INCLUDES@
#undef PIDGIN_GLOBAL_HEADER_INSIDE
#endif /* PIDGIN_PIDGIN_H */