samples: add Terra samples

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

samples/Terra/simplestruct.t

@@ -0,0 +1,10 @@
+
+struct A {
+	a : int
+}
+
+terra foo(a : &A)
+	return a
+end
+
+print(foo(terralib.new(A,{3})))