Remove init callback from object.{c, h}
Remove init callback from object subtypes

Remove init callback from array.c, set.c, string.c and wayland_obj.c
Remove init callback in message subtypes

Remove init callback in error_reply.c, message.c, reply.c, transaction.c
and value_reply.c
Remove init callbak from command/processor.c
Remove init callback from compositor object subtypes

Remove init callback from buffer.c, frame.c, image.c, cursor.c,
framebuffer_device.c, monitor.c and monitor_mode.c
Remove init callback from compositor/wayland subtypes
Remove init callback from tests

Remove init callback form attribute_test.c and ws_set/test.c
Merge pull request #303 from xVin/remove_init_callback

Remove init callback