Modified jsonPointer to create an empty Array for new integer key
flagrate.jsonPointer: for reliability - NOTE: now flagrate.jsonPointer.set() allows null value and use undefined to delete value.
related: 4d51553311988149a23a77b94f539e51160a2aa3
flagrate.Modal#open(): improve the behavior.
fixed problem with document.activeElement
flagrate.css: improved
flagrate.css: improved