samples: add Terra samples

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

samples/Terra/overload3.t

@@ -0,0 +1,15 @@
+
+terra foo(a : {int} )
+	return 1
+end
+
+terra foo(a : {int,int} )
+	return 2
+end
+
+terra doit()
+	return foo({1,2}) + foo({1,2})
+end
+
+local test = require("test")
+test.eq(doit(),4)