#101 Node - edge clipping

[bourqui]

When edges have bends, clipping on nodes is not done correctly as anchors computation does not take bends into account (cf graph example). Therefore if one uses bends + arrows, then the arrow is not displayed correctly.

To solve that issue, one should first traverse the bends to find the last bend that is inside the node and then use that last bend to compute node-edge clipping (already got David's approval).

[bourqui]