minor code cleaning and examples update

examples/exMat.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <latan/Io.hpp>
+#include <latan/Mat.hpp>
+
+using namespace std;
+using namespace Latan;
+
+int main(void)
+{
+    AsciiFile F;
+    DMat A,B;
+    const string fileName = "exMat.dat";
+    
+    // read
+    cout << "-- reading " << fileName << "..." << endl;
+    F.open(fileName, File::Mode::read);
+    A = F.read<DMat>("A");
+    B = F.read<DMat>("B");
+    cout << "A=\n"   << A   << '\n' << endl;
+    cout << "B=\n"   << B   << '\n' << endl;
+    cout << "A*B=\n" << A*B << '\n' << endl;
+    F.close();
+    
+    // write
+    cout << "-- saving A*B..." << endl;
+    F.open(fileName, File::Mode::append);
+    F.save((A*B).eval(), "AB");
+    
+    return EXIT_SUCCESS;
+}