pidgin/pidgin

Update the demo protocol plugin to not depend on conversation names

We're starting to phase out conversation names as they don't work well with
modern stuff. So this goes ahead and fixes the not interactions in the demo
protocol.

I also generated the echo message in the send_message_async rather than in the
callback.

Testing Done:
Ran the turtles and send some messages to Echo on the demo protocol.

Reviewed at https://reviews.imfreedom.org/r/3135/
##############################################################################
# General Options
option('devenv-config-dir', type : 'string',
description : 'config directory for running a devenv (defaults to a subdirectory of buildroot)')
option('doc', type : 'boolean', value : false,
description : 'build documentation with gtk-doc')
option('extraversion', type : 'string',
description : 'extra version number to be displayed in Help->About and --help (for packagers)')
option('introspection', type : 'boolean', value : true,
description : 'build introspection data')
option('build-dependencies', type : 'boolean', value : false,
description : 'enable the use of subprojects to build missing dependencies.')
##############################################################################
# Libpurple Options
option('kwallet', type : 'feature',
description : 'enable KWallet support')
option('libsecret', type : 'feature',
description : 'enable libsecret support')
##############################################################################
# Protocol Plugins
option('avahi', type : 'feature',
description : 'compile with avahi (required for Bonjour support)')
option('dynamic-prpls', type : 'string', value: 'all',
description : 'specify which protocols to build dynamically')
option('libgadu', type : 'feature',
description : 'compile with libgadu (required for GaduGadu support)')
##############################################################################
# Pidgin Options
option('console-logging', type : 'boolean', value : false,
description : 'compile with console logging support')
option('gtkui', type : 'boolean', value : true,
description : 'compile with GTK+ user interface')
option('unity-integration', type : 'feature', value : 'disabled',
description : 'compile with support for unity integration plugin')