- [bug] Fixed cextension bug whereby the

- [bug] Fixed cextension bug whereby the
"ambiguous column error" would fail to
function properly if the given index were
a Column object and not a string.
Note there are still some column-targeting
issues here which are fixed in 0.8.
[ticket:2553]
- find more cases where column targeting is being inaccurate, add
more information to result_map to better differentiate "ambiguous"
results from "present" or "not present".  In particular, result_map
is sensitive to dupes, even though no error is raised; the conflicting
columns are added to the "obj" member of the tuple so that the two
are both directly accessible in the result proxy
- handwringing over the damn "name fallback" thing in results.  can't
really make it perfect yet
- fix up oracle returning clause.  not sure why its guarding against
labels, remove that for now and see what the bot says.