samples: add Terra samples

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

samples/Terra/opaquealloc.t

@@ -0,0 +1,19 @@
+
+
+
+local r,e = pcall(function()
+	local struct A {
+		a : opaque
+	}
+	local v = terralib.new(A)
+end)
+
+assert(not r and e:match("Errors reported during"))
+
+
+local r,e = pcall(function()
+	local v = terralib.new(opaque)
+end)
+
+
+assert(not r and e:match("attempting to use an opaque type"))