Add NativeProblem that loads libeva2problem.jnilib if present.

closes #47

src/eva2/problems/NativeProblem.java

@@ -0,0 +1,27 @@
+package eva2.problems;
+
+/**
+ *
+ */
+public class NativeProblem extends AbstractProblemDouble {
+
+    private static boolean isLibraryLoaded = false;
+
+    public NativeProblem() {
+        if (!isLibraryLoaded) {
+            System.loadLibrary("eva2problem");
+        }
+        isLibraryLoaded = true;
+    }
+
+    @Override
+    public native double[] evaluate(double[] x);
+
+    @Override
+    public native String getName();
+
+    @Override
+    public Object clone() {
+        return this.clone();
+    }
+}