Add getter for pair in Filter object

Since the unit-tests were using the pair instead of a Filter object, a getter
has been created for the pair.

For more informations, see #3283.

algo/core/filter.cpp

@@ -120,3 +120,7 @@ BioReader FilterWithACAutomaton::filterBioReaderWithACAutomaton(
   }
   return (result.size() == 0) ? origin : result;
 }
+
+pair<vector<int>*, AbstractACAutomaton<KmerAffect>*>*  FilterWithACAutomaton::getPair(){
+  return this->p;
+}

algo/core/filter.h

@@ -81,5 +81,7 @@ class FilterWithACAutomaton {
     the seed has a size of 10.
   */
   void buildACAutomatonToFilterBioReader(BioReader &origin, string seed);
+
+  pair<vector<int>*, AbstractACAutomaton<KmerAffect>*>* getPair();
 };
 #endif