Fix matrix multiplication order in point-based gluing

[ahoenselaar]

Closes #1651

Let:

• $\mathbf{p}_{\text{local}}$ be a point in the local coordinate space of the free mesh.
• $T_{\text{old}}$ be the current transformation matrix of the free mesh (currentNode()->tr()).
• $\mathbf{p}_{\text{global}} = T_{\text{old}} \cdot \mathbf{p}_{\text{local}}$ be the point's current global position.
• $R$ be the alignment/registration transformation matrix (res) computed by ComputeRigidMatchMatrix or ComputeSimilarityMatchMatrix.

The registration algorithm finds a transformation $R$ that registers the picked points $\mathbf{p}_{\text{free, global}}$ to the glued points $\mathbf{p}_{\text{glued, global}}$, both of which are in global coordinates. Therefore, the registered global position is:
$\mathbf{p}_{\text{global, new}} = R \cdot \mathbf{p}_{\text{global, old}}$

Substituting the definition of $\mathbf{p}_{\text{global}}$:
$\mathbf{p}_{\text{global, new}} = R \cdot (T_{\text{old}} \cdot \mathbf{p}_{\text{local}}) = (R \cdot T_{\text{old}}) \cdot \mathbf{p}_{\text{local}}$

Then the new transformation matrix of the mesh must be:
$$T_{\text{new}} = R \cdot T_{\text{old}}$$
which is pre-multiplication (res * currentNode()->tr()).