2.3.0 -> 2.3.1
- critical: fixed angular momentum computation. Version 2.3.0 produced wrong
  results Thanks to Hilario Tome and Benjamin Michaud for reporting!
- critical: fixed JointTypeEulerZYX. Previous versions produce wrong
  results!
- fixed library version number for the LuaModel addon. It now uses version
  2.3 instead of the wrong 2.2.

2.2.2 -> 2.3.0
- disabled clearing of joint space inertia matrix in CRBA.
  It is expected that the matrix is cleared by the user when neccessary.
- Added experimental joint type JointTypeEulerZYX. It does not emulate
  multiple degrees of freedom using virtual bodies instead it uses a 3 DoF
  motion subspace. Performance is better for the
  CompositeRigidBodyAlgorithm but worse for other algorithms.
- Using Eigen3's default column-major ordering for matrices when using
  Eigen3. This should have no effect for the user unless matrix elements
  are accessed using the .data()[i] operator of Eigen3's matrix class. However
  if .data()[i] is used the access indices have to be adjusted.
- added functions to compute kinetic and potential energy and the
  computation of the center of mass and its linear velocity:
    RigidBodyDynamics::Utils::CalcCenterOfMass
    RigidBodyDynamics::Utils::CalcPotentialEnergy
    RigidBodyDynamics::Utils::CalcKineticEnergy
    RigidBodyDynamics::Utils::CalcAngularMomentum

2.2.1 -> 2.2.2
- adjusted default constructor for Body. It now has the identity matrix as
  inertia, instead of a zero matrix.
- LuaModel: made sure that the Body value is optional and uses the default
  Body constructor if not defined.

2.2.0 -> 2.2.1
- properly exporting LuaTables++ functions when using LuaModel addon
  Fixes linking 
- fixed exported library version (now at 2.2 as expected)

2.1.0 -> 2.2.0
- added spherical joints that do not suffer from singularities:
  Use joint type JointTypeSpherical
- added Model::q_size, and Model::qdot_size that report the sizes including
  all 4 Quaternion parameters when spherical joints are used.
  User is advised to use Model::q_size and Model::qdot_size instead of
  Model::dof_count.
- removed "constraint_" prefix from constraint impulses, forces and
  accelerations from the ConstraintSets:
  renaming required if values are queried  
- Contact impulses: specification of a contact velocity after a collision:
  added ConstraintSet::v_plus which can be set for the desired constraint
  velocity after a collision. Previously it used the values stored in 
  ConstraintSet::constraint_acceleration.
  User has to store desired exit velocities manually in CS::v_plus

2.0.1 -> 2.1.0
- made codebase compatible to Debian
  Binary symbol export was changed. No change in user code required,
  however everything needs to be recompiled and linked.
- Removed Lua 5.2 source
  When building the addon LuaModel, one hast to have it installed on the
  system already.
- Removed UnitTest++ sources
  When building tests one has to have it installed on the system already.

2.0.0 -> 2.0.1
- fixed compiler errors on some older compilers
  No change required when using RBDL version 2.0.0.
- fixed CMake configurations for examples
  No change required when using RBDL version 2.0.0.

1.X.Y -> 2.0.0
- removed Model::Init():
  All initialization is now done in the default constructor in Model(). To
  be compatible with the new API simply remove any calls to Model::Init().
- removed Eigen3 sources:
  Eigen3 is no more included in RBDL instead it uses the Eigen3 library
  that is installed on the system. If you want to use RBDL with Eigen3
  you have to install it on your system yourself.
- inverted sign of contact forces/impulses:
  ConstraintSet::constraint_force and ConstraintSet::constraint_impulse are
  now the forces or impulses that are acting on the constrained body by the
  constraint.

1.0.0 -> 1.1.0
- removed constructor Body (mass, com, length, gyration_radii)
  This constructor did some erroneous calculations to compute the real
  radii of gyration. It was removed as the two remaining constructors are
  properly tested and are more general.
