Implementation of 0D grid for analysis of collisional operators.

Still need to add a 0D pusher and the corresponding input configuration
and documentation.

src/modules/mesh/moduleMesh.f90

@@ -193,7 +193,6 @@ MODULE moduleMesh
     END SUBROUTINE scatter_interface
 
     PURE FUNCTION gatherEF_interface(self, xi) RESULT(EF)
-      
       IMPORT:: meshVol
       CLASS(meshVol), INTENT(in):: self
       REAL(8), INTENT(in):: xi(1:3)
@@ -655,7 +654,7 @@ MODULE moduleMesh
     END SUBROUTINE doCollisions
 
     SUBROUTINE doCoulomb(self)
-      IMPORT meshParticles
+      IMPLICIT NONE
 
       CLASS(meshParticles), INTENT(inout):: self