Added MathUtil.floorDiv, and tests.

src/test/java/pythagoras/i/MathUtilTest.java

@@ -0,0 +1,22 @@
+//
+// Pythagoras - a collection of geometry classes
+// http://github.com/samskivert/pythagoras
+
+package pythagoras.i;
+
+import org.junit.*;
+import static org.junit.Assert.*;
+
+/**
+ * Tests parts of the {@link MathUtil} class.
+ */
+public class MathUtilTest
+{
+    @Test public void testFloorDiv () {
+        int[] nums = { -15, -10, -8, -2, 0, 2, 8, 10, 15 };
+        int[] vals = {  -2,  -1, -1, -1, 0, 0, 0,  1,  1 };
+        for (int ii = 0; ii < nums.length; ii++) {
+            assertEquals(vals[ii], MathUtil.floorDiv(nums[ii], 10));
+        }
+    }
+}