[273,107]	Ring Buffers

RB.C		Library routines to handle ring buffers of items,
		where all items in a ring buffer are the same size.
		Different ring buffers can have different item sizes.
		Use DECUS C tool GETRNO to get documentation.

RB.H		Needed for use with struct "rb".

RBTEST.C	Crude test & demo of RB.C.
