Replaced /freq command line option with /delay

 * /freq was undocumented, but for /delay added help
 * /freq was not accurate when using high values
 * /delay busy waits to delay the communication
 * useful for when the JTAG cable is not reliable

Signed-off-by: Mansour Behabadi <mansour@oxplot.com>
Updated README to mention /delay:N option

Signed-off-by: Mansour Behabadi <mansour@oxplot.com>