Improve reading line
Inversing the parameter is not a good idea
Remove json-read-from-string nil which explode
Improve dealing with checkbox properties.
Do not permit duplicates in the checkbox metadata.
Using marker to get back to it + orgtrello-id contains the marker the
first around (no other entries than orgtrello-id)
No longer needed the marker cleanup, we need.
Improve readability
No duplicates when setting a property.
Improved decorator - where is the polymorphism and the multiple arity
definition again? (ah yes, clj...)
Fix multiple small problems.
Improve the cleanup
Abstract org up to deal with checkbox.