Remove FBDialect.get_column_sequence

[Lele Gaifax]

This is just to remind that Michael asked to remove the method in question, that uses an heuristic to determine whether a column is linked to a sequence through a trigger.

Removing it means that such columns won't be fully reflected.

Maybe the method could be left there to be called explicitly, stripping away just the final step of .get_columns().

[Lele Gaifax]

In particular, Michael didn't like the use of the ''sequence'' slot of the dictionary describing each column.

[Mike Bayer]

there are at least four dialects doing this, using the 'sequence' column sent to the inspector (oddly enough for databases that don't support explicit sequences but instead IDENTITY types). At this point the usage of Sequence for IDENTITY is pretty well established since it works on the CREATE TABLE side. For FB and PG, which have a way of associating a Sequence with a column, I think it's fine. The PG dialect could be made to do this also (at the moment it just sets the "autoincrement" flag).

[Mike Bayer]

Removing milestone: 0.6.0 (automated comment)