TODO WIP Support Yesod 1.1 new logging system...

TODO check whether we've lost functionality
Freeze yesod-platform to 1.1.7.2 and relax other constraints
Remove now-redundant backported radioFieldList
fixup! TODO WIP Support Yesod 1.1 new logging system
widgetFile now takes a "settings" argument
mkDeleteCascade now takes settings
Key is now a type family, KeyBackend is the newtype
JS interpolation is finally typesafe, sprinkle toJSON
TODO WIP Persistent shuffled its types around again...

TODO work out what the new type signatures should be
TODO WIP we won't compile without warnings for now
TODO WIP old logging bits
TODO WIP old DB function type signatures