samples: add Terra samples

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

samples/Terra/antiquote4.t

@@ -0,0 +1,11 @@
+
+
+terra foo()
+	var a = 4
+	return [a]
+end
+
+foo:printpretty()
+
+local test = require("test")
+test.eq(foo(),4)