fix new warnings and escape apply namespace

- `std::apply` is part of C++17 and the compiler wants to use it because
of ADL. Thus it is now necessary to escape it as `::apply`.
- remove some `using namespace std` remaining in the sources.
- fix simple warnings.

eo/src/eoInitializer.h

@@ -105,10 +105,10 @@ public:
     virtual void operator() ()
     {
         eoPop<POT> empty_pop;
-        apply(proc, pop);
+        ::apply(proc, pop);
         procPara(empty_pop, pop);
-        apply < POT > (initVelo, pop);
-        apply < POT > (initBest, pop);
+        ::apply < POT > (initVelo, pop);
+        ::apply < POT > (initBest, pop);
         topology.setup(pop);
     }