Add a sort algorithm for Protein (as in Victor branch)

src/libaevol/Protein.cpp

@@ -756,6 +756,15 @@ void Protein::save(gzFile backup_file)
     AA->save(backup_file);
 }
 
+// =================================================================
+//                        Overloaded Operators
+// =================================================================
+    bool Protein::operator<(const Protein & other){
+      return (height_ <  other.height_)
+             || (height_ == other.height_ && mean_ < other.mean_)
+             || (height_ == other.height_ && mean_ == other.mean_ && width_ < other.width_);
+    }
+
 // =================================================================
 //                           Protected Methods
 // =================================================================

src/libaevol/Protein.h

@@ -118,6 +118,7 @@ class Protein
     void  add_RNA(Rna * rna);
     char* AA_sequence(char separator = ' ') const; // WARNING : creates a new char[...] (up to you to delete it!)
     virtual void  save(gzFile backup_file);
+    bool operator<(const Protein & other);
 
     // =================================================================
     //                           Public Attributes