forwards compat for 0.4

[Mike Bayer]

• most of the 0.4 test test/orm/query.py should run in 0.3.9, testing all()/one()/first(), add this test.
• once the "bind" argument to everything that can connect to an engine is figured out, add this argument everywhere to 0.3.9 as well with identical behavior.
• ensure MetaData/ThreadLocalMetaData names/constructors exist the way they will in 0.4

I think theres more to add to this list.

[jek]

compatible metadata constructors are in changeset:2856

[Mike Bayer]

all three are done plus lots of new docs.

[Mike Bayer]

Removing milestone: 0.3.9 (automated comment)