Fix out of order tail issue

While experimenting, I stumbled on a issue where tails get inserted out of order if put under the right stress.

Test (the case below is absurd, but I had to recreate the issue without the extension I was testing):
```
This should remain in order:

***I am ___italic_ and__ bold* I am `just` bold**
```

Expected compared against actual:
```diff
--- right.html	Fri Oct 17 09:28:35 2014
+++ wrong.html	Fri Oct 17 09:28:26 2014
@@ -1,2 +1,2 @@
 <p>This should remain in order:</p>
-<p><strong><em>I am <strong><em>italic</em> and</strong> bold</em> I am <code>just</code> bold</strong></p>
+<p><strong><code>just</code> bold<em>I am <strong><em>italic</em> and</strong> bold</em> I am </strong></p>
```

The fix was very straight forward.  Tails of subnodes, when inserted back into the parent, should be inserted after the subnode.