Done:
* Creating new local day cycles.
* Editing existing local day cycles.
* Deleting day cycles.
To do:
* Editing region day cycle, dealing with skies in region scope.
* Handle teleport while editing a day cycle.
* Update UI when a day cycle or sky preset gets deleted.
* Make the time ctrl increase/decrease consistently.
Implemented time spin control which is like spin control, but shows and allows to edit time string in "hh:mm PM/AM" format.
Implemented according to the WLRS spec.