generalize dbio to support non-file IOs
update vera migrations
add ScatterView to urls
don't generate choice lists for unregistered models
allow anonymous usage
ignore relationship data unless item_id is present
register site and parameter by default
auto skip column screen if no disambiguation is needed
update tests
support 'vertical' table layouts in import_data()
remove unused caching functionality (fixes #27)
tool to help resolve identifiers in row data
update additional metadata if present
ignore metacolumns with no type
compatibility fixes

- remove proxy model in favor of files dependency on dbio
- fix ordering issues
v0.6.0