added the zeroed initialization
Modified the API. Now the setQ and setDq methods are replaced with setState
Now the S matrix is a cell array to allow mutiple DOF joints
Added a submatrix representation of D and b. Removed setQ and setDq with setState
Gravity computed in the initialization. S replaced with a cell array
Gravity computed in the initialization. S replaced with a cell array
Gravity computed in the initialization. S replaced with a cell array
Gravity computed in the initialization. S replaced with a cell array