samples: add Terra samples

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

samples/Terra/vars.t

@@ -0,0 +1,23 @@
+
+
+a = {}
+a.b, a.c = global(3),global(double,4)
+d = global(5)
+--print(a.b)
+
+--a.b:gettype(nil)
+
+terra bar()
+    a.b = a.b + 1
+    a.c = a.c + 1
+    d = d + 1
+end
+terra foo()
+    return a.b,a.c,d
+end
+
+
+local test = require("test")
+
+bar()
+test.meq({4,5,6},foo())