adding error code returns to relevant functions
switching to returning error_codes directly
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.
added move_group python interface bindings to move group interface
function:
void setPathConstraints(const moveit_msgs::Constraint &constraint)
in order to be able to set path constraints from python scripts
directly and no need to use the DB.
Retrieve from the movegroup the current path constraints

now it is possible to retreve as a moveit_msgs::Constreints
the current path constraints for a group to be hable to maniputlate
them from cpp. Function is:

moveit::planning_interface::MoveGroup::getPathConstraints() const

This function is also added to the python bindings in order to
be ussable for python and moveit_commander package.

fixed a incohrence in naming the python call for set the constrains
from a msg object.

Addd bindings to this functionality to the python wraprre
added a little more vervose documentation
Merge pull request #438 from ibec-robotics/add_functions_to_python_bindings

Add functions to python bindings
Merge pull request #430 from davetcoleman/kdl_minor_changes

Minor non-functional changes to KDL
Merge pull request #437 from pal-robotics/re-issue-421

Use member NodeHandle in action clients.
adding constructors, simplifying return, changing to pointer, adding null for default argument
Removing line that's not being used.
Merge pull request #429 from ros-planning/error_codes_minimal

Changing API to return error codes (bool return value will also work)
update build system for ROS indigo
Merge pull request #440 from isucan/hydro-devel

update build system for ROS indigo (compatible with hydro)
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
Merge pull request #441 from v4hn/find-pkgconfig-hydro

find PkgConfig before using pkg_check_modules