Expanded array tests, read more

Getting the array's length is still not available yet, so I'm not
marking arrays as done - but everything that is there is tested.

I've also tweaked the assert output callbacks to also print 'assert failure'.

tests/integrations/test_arrays.toy

@@ -0,0 +1,17 @@
+//1-D array
+var arr = [1, 2, 3];
+arr[1] = 6;
+
+assert arr == [1, 6, 3], "1-D array failed";
+
+//we need to go deeper
+var barr = [
+	[1, 2, 3],
+	[4, 5, 6],
+	[7, 8, 9]
+];
+
+barr[1][1] = 99;
+
+assert barr == [[1, 2, 3],[4,99,6],[7,8,9]], "2-D array failed";
+