have select's compile additional where clauses from bind params

[Mike Bayer]

if you do:

table.select().execute(user_id=7)

it should compile as though you did:

table.select(table.c.user_id==bindparam('user_id')).execute(user_id=7)

or just

table.select(table.c.user_id==7).execute()

this is somewhat like the select_by thing in mapper, in that key/value pairs become WHERE claues, or also like table.insert().execute(x=7), in that the bind params set to the execution get factored into the compilation of the clause.

[Mike Bayer]

commited in changeset:729