Add check for planning scene monitor connection, with 5 sec delay
Use member NodeHandle in action clients.

Currently services and topics are already using the member NodeHandle instance,
but not the action clients.

This is relevant for two reasons:
- Consistency in the resulting ROS API namespace (everything in the same namespace).
- Consistency in the spinning policy. All services, topics and actions will be spinned
  by the same NodeHandle, and whatever custom (or not) spinners and callback queues it
  has associated.
Fix initialization reorder warning.
adding error code returns to relevant functions
switching to returning error_codes directly
adding constructors, simplifying return, changing to pointer, adding null for default argument
Removing line that's not being used.
update build system for ROS indigo
update changelog
0.5.17
update dep for opencv to maintain consistency between hydro & indigo
find PkgConfig before using pkg_check_modules

PC specific functions mustn't be used before including PkgConfig
add pkg-config as dep
update changelog
0.5.18
Now check if there is a time for the gripper trajectory.

If there is a time, use that one on the gripper trajectory, if not, keep
with the previous strategy of using a default time.
Merge branch 'get_planning_scene_check' into hydro-devel
Fix
Improved error messages