addBody adds a body to the end of the chain
 
    THIS METHOD IS NO LONGER THE PREFERRED WAY OF SETTING UP A
    NEW KINEMATICS OBJECT. PLEASE LOAD FROM AN .HRDF FILE.  FOR
    MORE INFORMATION, PLEASE SEE:
    http://docs.hebi.us/tools.html#robot-description-format
 
    This method creates a serial chain of bodies that describe
    the kinematic relation of a robot. A 'body' can be a rigid
    link as well as a dynamic element. More detailed
    documentation on body types and parameters can be found at:
    http://docs.hebi.us/hardware.html#Kinematic_Info
 
    The 'Type' argument specifies the type of module or body
    that should be added. Currently implemented types include:
 
      X-Series Types            Required Parameters
        'X5-1'
        'X5-4'
        'X5-9'
        'X8-3'
        'X8-9'
        'X8-16'
        'X5-Link'               (Extension, Twist)
        'X5-LightBracket'       (Mounting)
        'X5-HeavyBracket'       (Mounting)
        'R8-3'
        'R8-9'
        'R8-16'
 
      Custom Types
        'GenericJoint'          (Axis)
        'GenericLink'           (CoM, OutputTransform, Mass )
 
    Some types may require a set of parameters. Parameters
    that are not required by the specified type are ignored.
    Potential kinematic parameters include:
 
        Parameter          Size    Units      Synonyms
        'Extension'        1x1     [m]        ('ext')
        'Twist'            1x1     [rad]
        'Mass'             1x1     [kg]
        'CoM'              3x1     [m]
        'Axis'             1x1     [tx|ty|tz|rx|ry|rz]
        'OutputTransform'  4x4                ('output','out')
        'Mounting'         1x1     [left|...] ('mount')
 
    Additionally, there are optional parameters that can be used
    to control the behavior of joints when calculating inverse
    kinematics with HEBIKINEMATICS, or generating trajectories
    with HEBITRAJECTORYGENERATOR. Joint limits are applicable
    to all joints and expect a [min max] vector without NaN.
 
        Parameter          Size    Units      Synonyms
        'PositionLimit'    1x2     [rad|m]    ('PosLim')
        'VelocityLimit'    1x2     [rad/s]    ('VelLim')
        'EffortLimit'      1x2     [Nm]     ('EffLim')
        'Mass'             1x1     [kg]
 
    Example
       % Setup a common 5 DoF X-Series arm configuration
       kin = HebiKinematics();
       kin.addBody('X5-9', 'PosLim', [-pi +pi]);
       kin.addBody('X5-HeavyBracket', 'mount', 'right-outside');
       kin.addBody('X5-4');
       kin.addBody('X5-Link', 'ext', 0.350, 'twist', pi/2);
       kin.addBody('X5-4');
       kin.addBody('X5-Link', 'ext', 0.250, 'twist', pi/2);
       kin.addBody('X5-1');
       kin.addBody('X5-LightBracket', 'mount', 'right');
       kin.addBody('X5-1');
 
    More general info on kinematics can be found at:
    http://docs.hebi.us/core_concepts.html#kinematics