- move pretty much all of sqlalchemy.testing over for now, as we'd

- move pretty much all of sqlalchemy.testing over for now, as we'd
like to run tests against 0.8 and even late 0.7 versions with the same
capabilities, as well as run parallel testing against all of them.
we need a consistent system to get that all to work, so for now
we have the whole SQLA system shoved into here, not ideal but we have
a very good testing situation for now.  Once we target 0.9.4 at the lowest
we should be able to move all this out.
- re-support 0.7, starting at 0.7.6 which is where things mostly work.
All tests, taking into account known skips and fails which are
added here for 0.7, early 0.8s, pass on 0.7.9.