A node to generate simulated time at a configurable rate.
Added update frequency of simulated clock.
Adding structure for wait action.
Added wait node action with service to preempt whatever wait is in progress.
Fixed preemption.
Fixed preemption as set_preempted was not sending internal signal.
Added correct empty response.
Added the change to wait action that kept the node from crashing
Merge remote-tracking branch 'origin/hydro-devel' into hydro-devel
Revert "Added the change to wait action that kept the node from crashing"

This reverts commit 6ff4ec93b93911e9a0832d46c0846e781fe0740f.
Readying for move.
Adding wait_action to strands_executive
Readying for move to strands_executive.
Adding sim_clock