samples: add Terra samples

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

samples/Terra/structarg.t

@@ -0,0 +1,9 @@
+terra foobar()
+    var a = { a=3,b=4}
+    var b = {a=5,b=6.0}
+    b = a
+	return a.a
+end
+
+local test = require("test")
+test.eq(foobar(),3)