Removed "using namespace std" statements from header files in EO -- "std::" identifier were added where necessary.

eo/tutorial/Lesson2/FirstRealEA.cpp

@@ -20,6 +20,9 @@
 // define your individuals
 typedef eoReal<double> Indi;	
 
+// Use functions from namespace std
+using namespace std;
+
 // EVALFUNC
 //-----------------------------------------------------------------------------
 // a simple fitness function that computes the euclidian norm of a real vector