Commander: error on unaligned reads sizes.
Commander: error on unaligned reads sizes.

Also improved help text for read/write commands.

mbedmicro/pyOCD,pyocd/pyOCD,mesheven/pyOCD,flit/pyOCD,mesheven/pyOCD,pyocd/pyOCD,mbedmicro/pyOCD,mesheven/pyOCD,mbedmicro/pyOCD,flit/pyOCD