Fixed return with no argument.

Closes GH-3.

Author: Kodiologist

py2hy/translate.hy

@@ -51,7 +51,7 @@
           ~@(T x.body))
 
       Return
-        `(return ~(T x.value))
+        `(return ~@(when x.value [(T x.value)]))
       Delete
         `(del ~@(T x.targets))
       Assign

tests/test_misc.hy

@@ -41,6 +41,13 @@
   (check "x[::-2]"   '(cut x None None -2)))
 
 
+(defn test-return []
+  ; https://github.com/hylang/py2hy/issues/3
+  (assert (= (2hy "return 1")    '(return 1)))
+  (assert (= (2hy "return None") '(return None)))
+  (assert (= (2hy "return")      '(return))))
+
+
 (defn test-chained-assignment []
   ; https://github.com/hylang/py2hy/issues/2