samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/forlist2.t

@@ -0,0 +1,37 @@
+
+
+struct Array {
+    data : int[3];
+}
+Array.metamethods.__for = function(syms,iter,body)
+    local pe = symbol()
+    local e = `@pe
+    return {e}, quote
+        var it = &iter
+        for i = 0,3 do
+            var [pe] = &it.data[i]
+            body
+        end
+    end
+end
+
+terra foo()
+    var a = Array{ array(1,2,3) }
+    for i in a do
+        i = i + 1
+    end
+    return a.data[0] + a.data[1] + a.data[2]
+end
+
+terra foo2()
+    var a = Array{ array(1,2,3) }
+    var s = 0
+    for i : double in a do
+        s = s + i
+    end
+    return s
+end
+
+assert(foo() == 9)
+
+assert(foo2() == 6)