Rework/global edit to enforce type templating of fermion operators.

Allows multi-precision work and paves the way for alternate BC's and such like
allowing for example G-parity which is important for K pipi programme.
In particular, can drive an extra flavour index into the fermion fields
using template types.

lib/qcd/action/fermion/OverlapWilsonCayleyZolotarevFermion.h

@@ -7,13 +7,16 @@ namespace Grid {
 
   namespace QCD {
 
-    class OverlapWilsonCayleyZolotarevFermion : public MobiusZolotarevFermion
+    template<class Impl>
+    class OverlapWilsonCayleyZolotarevFermion : public MobiusZolotarevFermion<Impl>
     {
     public:
+#include <qcd/action/fermion/FermionImplTypedefs.h>
+    public:
 
       // Constructors
 
-    OverlapWilsonCayleyZolotarevFermion(LatticeGaugeField &_Umu,
+    OverlapWilsonCayleyZolotarevFermion(GaugeField &_Umu,
 					GridCartesian         &FiveDimGrid,
 					GridRedBlackCartesian &FiveDimRedBlackGrid,
 					GridCartesian         &FourDimGrid,
@@ -21,7 +24,7 @@ namespace Grid {
 					RealD _mass,RealD _M5,
 					RealD lo, RealD hi) : 
       // b+c=1.0, b-c = 0 <=> b =c = 1/2
-      MobiusZolotarevFermion(_Umu,
+      MobiusZolotarevFermion<Impl>(_Umu,
 			     FiveDimGrid,
 			     FiveDimRedBlackGrid,
 			     FourDimGrid,