collection_classes based on dict fail on append

[Former user]

The setup for dict-based custom lists in {{{InstrumentedList}}} checks for an implementation of 'append' on the dict but fails to store it in {{{self._data_appender}}}. Patch attached.

-jek

[Former user]

patch

[Mike Bayer]

this bug was introduced post-0.3.7, so not a big disaster. patched in changeset:2497.

also was thinking that maybe we should support dictionaries that dont override __iter__(). this is doable but would require that all collection iteration within the ORM package use some new InstrumentedList method called iterate_values() or something like that.