[IMP] order wizard lines by name
[IMP] deal with modules whose models can't be loaded
[IMP] double quotes for docstring
[FIX] use exists query instead of huge in list
[IMP] hide unnecessary buttons in wizard II
[IMP] readability
[FIX] cope with purging nonexisting models
raw SQL query (but never read afterwards). Workaround for
lp:1277899
[FIX] Preserve dangling workflow table which is in use
[RFR] Group models per table when detecting columns to purge
to prevent problems with models sharing the same table
[ADD] Allow purging of dangling data entries
[FIX] Data purging now working
[IMP] Docstrings
[FIX] Label
[FIX] Catch attempt to unlink field from nonexisting model
[RFR] Flake8
Holger Brunn
Stefan Rijnhart