The trigger signal cannot be destroyed.

This enables to directly launch a python file within any roslaunch file
Adapted by F.Keith for the extraction of the messages.

Fixes #22

Conflicts:

	include/dynamic_graph_bridge/ros_interpreter.hh
	src/ros_interpreter.cpp

Deregister the signal formerly added.
Add a mutex system to prevent removing a signal while triggering it,
 to avoid a crash (especially if the topic was listened to).

  Without this call the command fails.

The old names are kept for now, but will disappear in the
future.

The old names are kept for now, but will disappear in the
future.

  Launching an application in a roslaunch file may cause to send python
  command before the interpreter has read the prologue. This commit should fix
  this issue.

Setting up ROS:
rosparam load `rospack find hrp2_14_description`/sot/hrp2_14_reduced.yaml
rosrun robot_state_publisher state_publisher

Display the robot using the info given in
https://trac.laas.fr/gepetto/hrp2/hrp2_14_description/html/reference/

To repeat at each simulation:
rosrun dynamic_graph_bridge geometric_simu --input-file ~/devel/ros-unstable-2/install/lib/libsot-hrp2-14-controller.so
rosrun dynamic_graph_bridge run_command
>>> from dynamic_graph.sot.application.velocity.precomputed_tasks import *
>>> solver=initialize(robot)
rosservice call /start_dynamic_graph
>>> Put_whatever_you_want_in_python

The rationale is to use a state vector map provided by the robot stack.
For instance for hrp-2 we have a yaml file providing the ros parameter:
/sot/state_vector_map
which specifies the state vector:
[RLEG_JOINT0, RLEG_JOINT1, RLEG_JOINT2, RLEG_JOINT3, RLEG_JOINT4, RLEG_JOINT5, LLEG_JOINT0,
  LLEG_JOINT1, LLEG_JOINT2, LLEG_JOINT3, LLEG_JOINT4, LLEG_JOINT5, CHEST_JOINT0, CHEST_JOINT1,
  HEAD_JOINT0, HEAD_JOINT1, RARM_JOINT0, RARM_JOINT1, RARM_JOINT2, RARM_JOINT3, RARM_JOINT4,
  RARM_JOINT5, RARM_JOINT6, LARM_JOINT0, LARM_JOINT1, LARM_JOINT2, LARM_JOINT3, LARM_JOINT4,
  LARM_JOINT5, LARM_JOINT6]

Pb: The openrtm architecture loads a shared library to implement the services of
an OpenRTM node. The scheduling properties are ensured by the operating system
running openrtm. Then on the robot, when the shared library is loaded it is
run inside the real-time loop. As sot-hrp-2 was creating the interpreter and
the ros-node in the constructor this used to break HRP-2 real-time OS.

This commit change the initialization of the ros-node to use a multi-threaded
spinner. Then ros calls are handled in a seperate non-realtime thread.

  Define entity RosTime that exports Ros time in a signal,
  add this entity in class dynamic_graph.ros.ros.Ros.
  Transfer Ros time in signal of type ptime instead of vector.

It happens, especially at init that vector are null (of size 0).
In this case, avoid abrupt failure by just copying the available
data instead of aborting the whole software.

Previous version of abstract-robot-dynamics did not contain the joint
name. Therefore, we had no way to forward the joint names to ROS.

This patch changes the ros_joint_state entity to add a
retrieveJointNames command. This command uses the pool to retrieve an
instance of the Dynamic entity (i.e. robot.dynamic) by using the
entity name. It then iterates on the robot structure to fill the joint
names in the message.

This command is automatically called in the Ros class so this change
is transparent for the end-user.

However, no more assumptions are made on the robot structure so the
sent message is exactly matching the robot structure loaded in the
dynamic entity. In particular, the free floating DOFs are sent and the
hard coded hand values have been removed.

ROS, in fact, requires DOF names and not joint names. Therefore, the
names are computed as follow:
- 0 dof: ignored,
- 1 dof: dof name is the joint name,
- >1 dof: <joint name>_<dof id>

    RosImport entity writes data from a signal to a ROS topic.

    Rename targets
      - dynamic_graph/ros/ros_import/wrap -> ros/ros_import/wrap,
      - dynamic_graph/ros/ros_export/wrap -> ros/ros_export/wrap,
      - dynamic_graph/ros/ros_joint_state/wrap -> ros/ros_joint_state/wrap.
    Add missing linking flags to target interpreter.
    Do not redefine PYTHON_SITELIB, use cmake/python.cmake definition.