* doc/dbus-specification.xml: update to describe 16-bit types and
	dict entries

	* dbus/dbus-marshal-basic.c (_dbus_unpack_uint16): fix broken
	assertion

	* dbus/dbus-protocol.h (DBUS_TYPE_DICT_ENTRY): add DICT_ENTRY as a
	type

	* dbus/dbus-marshal-recursive.c: implement