Attempt to wrap iterables

Instead of crashing when trying to unwrap an iterable, first expand it
and then try to wrap the resulting list.

This allows `unquote` to work with iterators and generators, which
previously didn't work unless you used `unquote-splice` or explicitly
expanded a list first.

hy/models.py

@@ -3,6 +3,7 @@
 # license. See the LICENSE.
 
 from __future__ import unicode_literals
+import collections
 from contextlib import contextmanager
 from math import isnan, isinf
 from hy._compat import PY3, str_type, bytes_type, long_type, string_types
@@ -62,9 +63,11 @@ def wrap_value(x):
 
     wrapper = _wrappers.get(type(x))
     if wrapper is None:
+        if (not isinstance(x, HyObject)
+            and isinstance(x, collections.Iterable)):
+            return wrap_value(list(x))
         return x
-    else:
-        return wrapper(x)
+    return wrapper(x)
 
 
 def replace_hy_obj(obj, other):

tests/native_tests/quote.hy

@@ -98,3 +98,12 @@
       [1 2 3]
       [4 5 6])
     [4 5 6])))
+
+(defn test-unquote-with-generators []
+  (defn values []
+    (yield '1)
+    (yield '2)
+    (yield '3))
+
+  (assert (= (eval `[~@(values)]) [1 2 3]))
+  (assert (= (eval `[~(values)]) [[1 2 3]])))