samples: add Terra samples

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

samples/Terra/completec.t

@@ -0,0 +1,13 @@
+C = terralib.includecstring [[
+    struct A {
+        int a;
+    };
+    static struct A foo;
+    struct A * getfoo() {
+        foo.a = 4;
+        return &foo;
+    }
+]]
+
+assert(C.getfoo().a == 4)
+