./adhoc-test [<options>] <nmra-command> <nmra-args...>    see nmra-packets.h
./adhoc-test [<options>] nmra_bytes <nmra-command-hex-no-csum>
./adhoc-test [<options>] nmra_raw <nmra-command-hex-with-csum>
./adhoc-test [<options>] command <literal-data-for-pic>
 options
  -s<serialport>   eg -s/dev/ttyS0  normally necessary
  -w<repeatdelay>  usleep; 0 = no usleep; default is -1 = don't repeat at all
  -i<iterations>   default is -1 = infinite; 0 or 1 means do only once
  -f<fudgedelay>   usleep; each character; default is 0 = no usleep

Eg,
 ./adhoc-test -s/dev/ttyS0 -w10000 -i1000 nmra_bytes 0348
to tell decoder 3 to go speed 13 backwards every 10ms for 1000 times, ie 10s
 (on norway this means it actually happens every 20ms, ie for 20s,
   which makes it a bit of a fudge really)

 ff       ff       80       e4       c1       17         output bytes
 11111111 11111111 10000000 11100100 11000001 00010111   as bits
 >1111111 >1111111 >0000000 >1100100 >1000001 $0010111   top bit: >/$ for pic

 1111111 1111111  0 00000011 0 01001000 0 01001011 1     reorg bits for nmra:
  preamble (14)   S 0AAAAAAA P 01DCSSSS 0 EEEEEEEE 1
                    03    (+)  48       = 4b ok

To test:
 ./adhoc-test -st nmra_bytes 0348 && binview t