EVENT#cancelDrag method added

This method cancels a drag operation.
Safety-checks for HEventResponder#setEnabled

These changes prevent issues of late calls, when the item is being destructed.
Destruction fix for text controls

Prevents #setEnabled to be re-called for a zombie item.
ELEM.make: added html option

When html is passed in the options (like styles and attr), the contents are set, when creating.
HTimeSheet refactoring

Ported HTimeSheet and HTimeSheetItem to CoffeeScript, fixed some issues and optimized the theme structure and styling; one nested element level less, shorter class names and precise matching.
Improved exception handling in HClass

Now outputs stack trace, function name, inner (base) and outer (extended) function source.
HTable optimization

Optimized HTable to work efficiently, when refreshed with values of varying amounts of rows. Also added the sortable option, which disables sorting, when set to false.