Katropton: Add supports for Gmsh 4

As observed by @R.Boman, katropton was not working with MPI using Gmsh 4. This was due to the fact that Gmsh 4 does not save the ghost cells by default.

To save those cells, we have to use the option -part_ghosts as discussed in the Gmsh doc.

However, this option is not supported by Gmsh 3 (gmsh -h | grep "ghost" does not find any line). Therefore, to solve this issue, the code must test the version of Gmsh used and, if the major version is 4 or greater, must add the -part_ghosts argument.

This MR includes the correction of if statements in plat*.geo which prevented the use of newer Gmsh than 3.0.6.

katropton/CMAME/mesh/plate.geo

 SetFactory("OpenCASCADE");
-If(GMSH_MAJOR_VERSION!=3 || GMSH_MINOR_VERSION!=0 || GMSH_PATCH_VERSION!=6)
+If(GMSH_MAJOR_VERSION<=3 && GMSH_MINOR_VERSION<=0 && GMSH_PATCH_VERSION<=6)
   Printf("gmsh %g.%g.%g is not supported by this .geo",GMSH_MAJOR_VERSION,GMSH_MINOR_VERSION,GMSH_PATCH_VERSION);
 Else
   LX = 10;