Switch pr2_etherCAT from doubles to ros::Time/ros::Duration (ros ticket #4995)

[ahendrix]

Use ros::Time ros::Duration values in pr2_etherCAT instead of doubles or {{{struct timespec}}}.

The problem with floating point values is they will loose precision as the seconds values returned by clock_getime increases.

Even though {{{struct timespec}}} stores sec and nsec values link ros::Time Using timespec values encourages poorly written implementation of durations :
{{{
(before.tv_sec + before.tv_nsec/NSEC_PER_SECOND) - (tick.tv_sec + tick.tv_nsec/NSEC_PER_SECOND)
}}}

trac data:

• Owner: dking
• Reporter: dking
• Reported at: Mon Jan 24 22:07:47 2011
• URL: https://code.ros.org/trac/wg-ros-pkg/ticket/4995