Fix AJAX comment posting.

When a comment was posted via AJAX the system did not read the existing
comments, therefore the returned value was empty. Fix this by adding a
proper comment list.
Added a ValueError to fix a nasty crash, reported and patched by https://github.com/maru-sama
Thanks!
Merge pull request #32 from maru-sama/fix-comments

Fix AJAX comment posting. This commit fixes #31
reverting my tests change - apparently the tests are always right