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

eo/tutorial/Lesson3/exercise3.1.cpp

@@ -25,6 +25,8 @@
 // define your genotype and fitness types
 typedef eoBit<eoMinimizingFitness> Indi;
 
+using namespace std;
+
 // the main_function: nothing changed(!), except variable initialization
 void main_function(int argc, char **argv)
 {