rtcds: now reads START_DELAY variable. restart --all fixed.

START_DELAY can be set to any value of seconds to change the default 15 second
delay after each model is started.  If the startup sequencer is used, the delay can be set to 1 second.

previously 'rtcds restart --all' would not restart the IOP model, since the kernel was unable to unload hte module before it was ordered to load it again.
Now, stopping a model waits until the kernel module is unloaded.