Firebird fails to reflect multifield FKs

[Former user]

The query used by the FB backend to autoload the FKs of a table does not produce the right information.

The attached patch fixes that, as well as the handling of NUMERIC datatype without an explicit precision.

I also took the opportunity of renaming some classes, to be more consistent with other backends.

Finally, I normalized the whitespace usage following PEP8.

With this patch all reflection tests pass under FB2.

[Former user]

Fix and cleanup

[Mike Bayer]

i like this patch, since youre taking control of the situation (which is good because i dont have firebird). changes look sane. committed this in changeset:2180