user import: corporations ...
Merge branch 'sf/import'
user import: former corporations, Sft, Nstft, ...
import: fixing import of external corporations to match new import mechanism.
user import: handle deceased (dt. verstorbene) users.
user import: consistency check for aktivitätszahl.
user import: beginning to fix issues that occured during import of corporation memberships.
import system: adding rake task 'import:all'.
import: fixing bootstrap rake task.
import: refactor old import tasks to match the new import mechanism.

Now, the complete import can be executed by
bundle exec rake import:all
user import: Nur in Verstorbenen-Gruppe eingtragen, wenn nicht ausgetreten.
user import: (1) fixing issue with import description column. (2) fixing issue of multiple tokens for the same corporation.