cleanup: revert remove of some for_each() templates

ippl/src/Field/AssignDefs.h

@@ -579,6 +579,14 @@ for_each(const IndexedBareFieldIterator<T,D>& p,
   return 0;
 }
 
+template<class T, class C, unsigned int D, unsigned int D1, class T1>
+inline int
+for_each(const BareFieldIterator<T,D>& /*p*/, 
+  const FillGCIfNecessaryTag<D1,T1> &, C)
+{
+  return 0;
+}
+
 template<class T, class C, unsigned int D, class T1>
 inline int
 for_each(const PETE_Scalar<T>&, const FillGCIfNecessaryTag<D,T1> &, C)

ippl/src/Utility/RNGAssignDefs.h

@@ -150,6 +150,18 @@ for_each(const SequenceGen<GT>& p, const EvalFunctor_3&)
   return p();
 }
 
+//
+// Does it have unit stride?
+// Not really a sensible question, but it is safe to say it does.
+//
+
+template<class GT, class C>
+inline bool
+for_each(const SequenceGen<GT>& /*p*/, HasUnitStride, C)
+{
+  return true;
+}
+
 //
 // RNG ignores step functor
 //