Added runge kutta integration.

test/integration.cpp

@@ -0,0 +1,26 @@
+#include <assert.h>
+#include <stdio.h>
+
+#include <matrix/integration.hpp>
+
+using namespace matrix;
+
+Vector<float, 6> f(float t, Vector<float, 6> y);
+
+Vector<float, 6> f(float t, Vector<float, 6> y) {
+    return ones<float, 6, 1>();
+}
+
+int main()
+{
+    Vector<float, 6> y = ones<float, 6, 1>();
+    float h = 1;
+    float t = 1;
+    y.T().print();
+    integrate_rk4(f, y, t, h);
+    y.T().print();
+    assert(y == (ones<float, 6, 1>()*2));
+    return 0;
+}
+
+/* vim: set et fenc=utf-8 ff=unix sts=0 sw=4 ts=4 : */