Allow saving SES to provided data storage

It is not always efficient (or possible) to use standard output
streams. Moreover, such generated result may be now further
processed.

examples/storage.hpp

@@ -0,0 +1,27 @@
+#ifndef DTL_STORAGE
+#define DTL_STORAGE
+
+#include <dtl/dtl.hpp>
+
+template <typename sesElem, typename storedData >
+class CustomStorage : public dtl::Storage < sesElem, storedData >
+{
+public :
+    CustomStorage(storedData& sd) : dtl::Storage < sesElem, storedData > (sd) {}
+    ~CustomStorage() {}
+    void operator() (const sesElem& se) const {
+        switch (se.second.type) {
+        case dtl::SES_ADD:
+            this->storedData_ = this->storedData_ + "Add: " + se.first + "\n";
+            break;
+        case dtl::SES_DELETE:
+            this->storedData_ = this->storedData_ + "Delete: " + se.first + "\n";
+            break;
+        case dtl::SES_COMMON:
+            this->storedData_ = this->storedData_ + "Common: " + se.first + "\n";
+            break;
+        }
+    }
+};
+
+#endif // DTL_STORAGE

examples/strdiff_storage.cpp

@@ -0,0 +1,38 @@
+#include <dtl/dtl.hpp>
+#include "common.hpp"
+#include <iostream>
+#include <string>
+
+#include "storage.hpp"
+
+using namespace std;
+
+using dtl::Diff;
+
+int main(int argc, char *argv[]){
+    
+    if (isFewArgs(argc)) {
+        cerr << "Too few arguments." << endl;
+        return -1;
+    }
+    
+    typedef char   elem;
+    typedef string sequence;
+
+    sequence A(argv[1]);
+    sequence B(argv[2]);
+    
+    Diff< elem, sequence > d(A, B);
+    d.compose();
+    
+    // Shortest Edit Script
+    cout << "SES" << endl;
+
+    string result;
+
+    d.storeSES < string, CustomStorage > (result);
+
+    cout << result;
+    
+    return 0;
+}