IPPE is now released in c !

Matlab implementation: minor bug fixes

• Handled the singularity when using Rodrigues' formula for aligning two vectors (Eq. 23 in the paper, variable t = 0).
• Handled non-rotation matrices being returned. This was caused by the line [modelRotation,sigs,~] = svd(U_*U_');. A check is needed to deal with det(modelRotation)=-1.