Functions to access the smart charger module has been added to the driver of the Darwin robot.
Allows to enable or disable module, set and get period, get smart charger's data (average time to empty and to full
and battery status), read smart charger's control register (smart charger detected and/or enabled), write limit current.

Minor changes to some of the examples.

Changed the sign of the pelvis yaw angle.

Removed some unnecessary cout's.
Enhanced some of the examples to fully test all the features.

Solved a bug in the codification of some of the walk parameters.

Solved a bug in the euler angles representation.
Added some kinematic parameters to the header files.

Solved a bug in the headers installation. Both arm and leg kinematics headers were not installed due to an error in the CMakeLists.txt file.

Added the Denavit Hartenberg parameters XML files for both legs.
Added a new example to test the legs kinematics.

Added an example to test the head tracking feature.

Added an example of use of the joints motion interface.

Added the current step to the action interface.

Set a variable with the path to the darwin firmware.

Removed the local copy of the dynamixel interface registers and used the firmware version.