add pickle capability to MetaData/Table

this has also been requested a bunch of times. slow reflection times lead to the need to be able to call up a MetaData with Tables, resulting from an earlier reflction, quickly. Various end-user serialization schemes, which seem to be overly complex, have been made. MetaData and Table should be able to just feed right into pickle.dumps() without issue. For MetaData which is bound, we just need to modify its pickling scheme to not include the "engine" parameter. upon de-pickling, just connect the metadata back to its engine. no big deal. should be doable with a small unit test by 4.0.

Comments (3)