Library: investigate / consolidate usages of type rebinding from iterators

...in an attempt to resolve the deeply nested problems encountered
while building an iterator pipeline for the Dispatcher. It seems
that I was sloppy some years ago and just "bashed them into submission",
thereby mixing up two different meanings of "value_type"

Moreover I seemingly implemented the same helper trait template twice,
so the first step is to switch all usages to meta::TypeBinding

src/lib/itertools.hpp

@@ -78,6 +78,7 @@
 
 
 #include "lib/iter-adapter.hpp"
+#include "lib/meta/value-type-binding.hpp"
 #include "lib/meta/function.hpp"
 #include "lib/meta/trait.hpp"
 #include "lib/wrapper.hpp"
@@ -94,7 +95,7 @@ namespace lib {
   using std::function;
   using util::unConst;
   
-  using lib::meta::RefTraits;
+  using lib::meta::TypeBinding;
   
   
   
@@ -753,9 +754,9 @@ namespace lib {
           return bool(source_);
         }
       
-      typedef typename RefTraits<VAL>::pointer pointer;
-      typedef typename RefTraits<VAL>::reference reference;
-      typedef typename RefTraits<VAL>::value_type value_type;
+      typedef typename TypeBinding<VAL>::pointer pointer;
+      typedef typename TypeBinding<VAL>::reference reference;
+      typedef typename TypeBinding<VAL>::value_type value_type;
     };