more test-order fixes

reset column information before we make assertions
Fix a bunch of test-ordering issues

put.the.candle.back
deal with HABTM on rails 4.1

in rails 4.1 they just create a class on demand to serve the HABTM
association, so if we want that on-slave by default we just gotta patch
it.
silence more 'specification needs to be symbol' warnings
setup DatabaseTasks to work without Rails loaded