Allow time zero in joint spline traj controller (ros ticket #3896)

[ahendrix]

When a trajectory with time zero comes in, the specified trajectory should start at the time the trajectory was received.

This solves the problem of having to pick the time you expect your trajectory to be received by the controller.

trac data:

• Owner: sglaser
• Reporter: wim
• Reported at: Fri Feb 19 14:33:44 2010
• URL: https://code.ros.org/trac/wg-ros-pkg/ticket/3896

[ahendrix]

[sglaser] r34807 in the JointTrajectoryActionController, which is slated for pr2_controllers 1.1.0