Add "send random number" menu option

Add a new option in the send menu to send a random integer from 0 to
1023 to each host. This can be used to spread load across resources
or delay the activation of commands to spread load across time.

e.g. sleep $(( [random] % 10)) &&
		fetch http://srv-$(( [random] % 5 )).small.server/file
Merge branch 'random' of https://github.com/cqexbesd/clusterssh into cqexbesd-random
Merge branch 'cqexbesd-random'
Record patch by Andrew (cqexbesd)