expose explosion.initialnormal to script for fine grained directional control

Engine/source/T3D/fx/explosion.cpp

@@ -962,7 +962,7 @@ void Explosion::setInitialState(const Point3F& point, const Point3F& normal, con
 void Explosion::initPersistFields()
 {
    Parent::initPersistFields();
-
+   addField("initialNormal", TypePoint3F, Offset(mInitialNormal, Explosion), "Initial starting Normal.");
    //
 }