New injection based on surface to all geometries.

WARNING: 3DCart still not working (too tired to calculate things and I'm
    not ussing it...)

src/modules/mesh/3DCart/moduleMesh3DCart.f90

@@ -109,6 +109,7 @@ MODULE moduleMesh3DCart
       USE moduleBoundary
       USE moduleErrors
       USE moduleMath
+      USE moduleRefParam, ONLY: L_ref
       IMPLICIT NONE
 
       CLASS(meshEdge3DCartTria), INTENT(out):: self
@@ -142,6 +143,8 @@ MODULE moduleMesh3DCart
       self%normal = crossProduct(vec1, vec2)
       self%normal = normalize(self%normal)
 
+      self%surface = 1.D0/L_ref**2 !TODO: FIX THIS WHEN MOVING TO 3D
+
       !Boundary index
       self%boundary => boundary(bt)
       ALLOCATE(self%fBoundary(1:nSpecies))