first example of automatic algorithm assembling

- add "Forges" tools, to wrap several operator with deferred
instanciation.
- add t-forge-algo to show how to enumerate several algorithms instances
from a common grammar and several alternative operators.
- add several missing className().

eo/src/eoSequentialSelect.h

@@ -84,6 +84,8 @@ private:
   bool ordered;
   unsigned current;
   std::vector<const EOT*> eoPters;
+public:
+  virtual std::string className() const {return "eoSequentialSelect";}
 };