samples: add Terra samples

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

samples/Terra/union.t

@@ -0,0 +1,26 @@
+
+struct A { a : int, union { c : int8[6], b : int }, d : float, union { e : int, f : float }, g : int }
+struct B { union { b : int , c : int8[6] }, a : int }
+local C = struct {  union { union { b : int}  , c : int8[6] }, w : int }
+terra foo()
+	var a : A
+	var b : B
+	var c : C
+	a.b = 4
+	a.a = 5
+	a.c[4] = 3
+	a.d = 4
+	return a.a + a.b + a.c[4] + a.d
+end
+
+struct Stuff { union { a : int, b : float } }
+
+terra what()
+	var a : Stuff, b : Stuff
+	a.a,b.a = 3,4
+	return a.b/b.b --== .75, this is the best bad interview question
+end
+
+local test = require("test")
+test.eq(foo(),16)
+test.eq(what(),.75)