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/2DCart/moduleMesh2DCart.f90

@@ -144,6 +144,7 @@ MODULE moduleMesh2DCart
       USE moduleSpecies
       USE moduleBoundary
       USE moduleErrors
+      USE moduleRefParam, ONLY: L_ref
       IMPLICIT NONE
 
       CLASS(meshEdge2DCart), INTENT(out):: self
@@ -163,7 +164,7 @@ MODULE moduleMesh2DCart
       r2 = self%n2%getCoordinates()
       self%x  = (/r1(1), r2(1)/)
       self%y  = (/r1(2), r2(2)/)
-      self%weight = 1.D0
+      self%surface = SQRT((self%x(2) - self%x(1))**2 + (self%y(2) - self%y(1))**2) / L_ref
       !Normal vector
       self%normal = (/ -(self%y(2)-self%y(1)), &
                          self%x(2)-self%x(1) , &