1.4.0

• extended JointDemo
• added TargetVelocityMotorHingeJoint
• added TargetAngleMotorHingeJoint
• made function names consistent
• fixed initialization of hinge joint coordinate system
• parallelized unified solver using graph coloring
• implemented unified solver for rigid bodies and deformable solids
• added documentation for generic constraints
• added generic constraint demo
• added generic constraint
• added coupling demo
• added ball joint which links a rigid body and a particle
• added universal joint
• improved hinge joint
• added documentation for position based fluids