8150785: (bf) Hoist slice and duplicate methods up to java.nio.Buffer
Reviewed-by: alanb, rriggs, chegar

8065570: (bf spec) ByteBuffer.slice() should make it clear that the initial order is BIG_ENDIAN
Summary: Refine documentation of allocate*(), wrap(), slice(), duplicate(), asReadOnlyBuffer(), and as{Type}Buffer() to explcitly state the byte order of the created buffer.
Reviewed-by: alanb