FIXED: bug that cannot set a value as empty
UPDATED: integrated part of event handler into core structure
UPDATED: enhanced row validity check
ADDED: not null constraint
TODO: forbid adding if there is format error
ADDED: integrated with masked input plugin, the UI looks more fun
Merge branch 'master' into zlk
Merge branch 'zlk' into czh
Merge branch 'zlk' of https://github.com/starrify/ymmbooking into zlk
Merge branch 'zlk' into czh
unchanged