Faster rip. Faster T3d-TOMAWAC coupling

I had a look at the coupling between TELEMAC-3D and TOMAWAC, as we are about to start to do some trials . I found two bottlenecks and rearranged the code, which gave a speed up of 30 to 35% (but I only tested a small part of the rip test case).Can you please check and review and if you approve merge?