New interface IInteractionMode: this interface will be used to set the robot
   in STIFF or COMPLIANT mode as a different way of interaction with the world.

 First implementation -- seems to work.
ControlBoardWrapper: Fix, un-paired '{' removed
yarp::dev: AddeIControlInterface2 which introduces the generic setControlMode method.
add new controlMode Mixed: accepts both position and velocity commands at the same time.
                    Force_idle: same as idle, but reset hardware faults, if any.

add vocabs for signalling special status from the board, if needed. Those are
                    Hardware Fault
                    Calibrating / Calib done
                    Not configured yet / Initial config done
IPositionDirect: add setPositionDirect method in IPositionDirect interface and
  relative implementation in the remoteControlBoard and in the controlBoardWrapper
Fix typo in IVelocityControlInterface
ControlBoardWrapper: add missing getControlModes group
Implement ControlInterface2: added implementation and declaration of IControl(1) methods
RemoteControlBoard: changed PositionDirectMode() to not use the iControl2 interface
ControlBoardWrapper: changed parsing of incoming setControlMode messages.
Fix error on PositionDirect(), added Torque()
ControlBoardWrapper: revert setPositionMode() to use iControlMode1->setPositionMode(j)
ControlBoardWrapper: fix add missinf break in a switch case
ControlBoardWrapper: Added switch case for iControlMode2 backward compatibility
Fix after rebasing
Better backward compatibility: impedance_pos e _vel propagated as 'legacy' up to
the motionControl devices instead remapping to the new interface iControlMode2 &
InteractionMode
ControlBoardWrapper: fix index remapping on new IControlMode2 interface
added VOCAB_IM_UNKNOWN, fixed windows issue
BugFix in ControlBoardWrapper2 - IControlMode2
ControlBoardWrapper2 : fix in setControlMode2
iOpenLoop: changes required by Randazz and other improvements

renamed setOutput in setRefOutput
added   getRefOutput
getOutput uses iOpenloop vocabs instead of PID interface ones
moved setRetOutput to streaming port instead of rpc to optimize
 high frequency settings
Update Yarp tweak version for tracking IOpenLoop API change

The IOpenLoopControl interface API has changed (check https://github.com/robotology/yarp/commit/52fedf60f9b903d5c6c3076ddcbee5926b7a03e4), we can change the tweak version so software using the new API can depend on a specific yarp version. 
I guess it will make sense to make a development release when the InteractionMode branch is merged with the master, but in the meanwhile it will be handy to increase the tweak version.