more documentation and examples, add Doxyfile and Mainpage.dox and also

the benchmark program

doc/benchmark.cpp

@@ -0,0 +1,23 @@
+// g++ -O3 -DNDEBUG benchmark.cpp -o benchmark && time ./benchmark
+
+#include "src/Core.h"
+
+using namespace std;
+USING_EIGEN_DATA_TYPES
+
+int main(int argc, char *argv[])
+{
+	Matrix3d I;
+	Matrix3d m;
+	for(int i = 0; i < 3; i++) for(int j = 0; j < 3; j++)
+	{
+		I(i,j) = (i==j);
+		m(i,j) = (i+3*j);
+	}
+	for(int a = 0; a < 100000000; a++)
+	{
+		m = I + 0.00005 * (m + m*m);
+	}
+	cout << m << endl;
+	return 0;
+}