grim/purple-plugin-pack

We stopped using plugin_pack.py awhile ago, so lets delete it finally
if TYPES.contains('default') and PURPLE.found()
dewysiwygification = shared_library('dewysiwygification',
'dewysiwygification.c',
dependencies : [PURPLE, GLIB],
name_prefix : '',
install : true,
install_dir : PURPLE_LIBDIR)
PP_PURPLE_BUILD += 'dewysiwygification'
endif