* dbus/dbus-internals.c: (_dbus_type_to_string):
	New function that returns a string describing a type.

	* dbus/dbus-marshal.c: (_dbus_demarshal_byte_array):
	* dbus/dbus-marshal.h:
	* dbus/dbus-message.c: (dbus_message_get_fields_valist),
	(dbus_message_iter_get_field_type), (dbus_message_iter_get_double),
	(dbus_message_iter_get_byte_array):
	* dbus/dbus-message.h:
	Add new convenience functions for appending and getting message fields.
	Also add demarshalling routines for byte arrays.