Main changes:

- Injection is now performed in parallalel (an IF statement could be
  required to avoid overhead when number of injected particles is
  below a margin).
- Added the possibility for multiple injections.

src/modules/moduleMesh.f95

@@ -59,6 +59,8 @@ MODULE moduleMesh
     INTEGER:: bt = 0
     CONTAINS
       PROCEDURE(initEdge_interface), DEFERRED, PASS:: init
+      PROCEDURE(boundary_interface), DEFERRED, PASS:: fBoundary
+      PROCEDURE(randPos_interface), DEFERRED, PASS::  randPos
 
   END TYPE meshEdge
 
@@ -73,6 +75,23 @@ MODULE moduleMesh
 
     END SUBROUTINE initEdge_interface
 
+    SUBROUTINE boundary_interface(self, part)
+      USE moduleSpecies
+
+      IMPORT:: meshEdge
+      CLASS (meshEdge), INTENT(inout):: self
+      CLASS (particle), INTENT(inout):: part
+
+    END SUBROUTINE
+
+    PURE FUNCTION randPos_interface(self, rnd) RESULT(r)
+      IMPORT:: meshEdge
+      CLASS(meshEdge), INTENT(in):: self
+      REAL(8), INTENT(in):: rnd
+      REAL(8):: r(1:3)
+
+    END FUNCTION randPos_interface
+
   END INTERFACE
 
   !Containers for edges in the mesh