pidgin/pidgin

Create PurpleProtocolWhiteboard and remove PurpleProtocolFactory

Testing Done:
Compiled

Reviewed at https://reviews.imfreedom.org/r/1809/
PURPLE_HISTORY_SOURCES = [
'purplehistorycore.c',
]
purple_history = executable('purple-history',
PURPLE_HISTORY_SOURCES,
dependencies : [libpurple_dep, glib],
install : true)