samples: add Terra samples

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

samples/Terra/methodrvalue.t

@@ -0,0 +1,18 @@
+--the zero line
+M = {}
+struct M.B {a : int, b : int}
+
+terra M.B:foo(a : int)
+    return self.a + a
+end
+
+terra rify()
+    var a = M.B { 1,2}
+    return a
+end
+terra bar()
+    return (rify()):foo(3)
+end
+
+test = require("test")
+test.eq(bar(),4)