- Partially fix: Cannot move card from one swimline to the other if moving in the same list; - Fix: Linking cards from empty board is possible and makes current board not load anymore.
- Partially fix: Cannot move card from one swimline to the other if moving in the same list;
- Fix: Linking cards from empty board is possible and makes current board not load anymore.

Thanks to andresmanelli !

Related #1887,
closes #1885

GhassenRjab/wekan,GhassenRjab/wekan,wekan/wekan,wekan/wekan,wekan/wekan,wekan/wekan,wekan/wekan,libreboard/libreboard,GhassenRjab/wekan,libreboard/libreboard