Changed code to calculate how the active item is close to start/end by length of items and index of active item.
Changed code to use fireAction with doDeleteFrom as the action instead of fireEvent so that 'itemremoved' can be 'preventable'.
Changed order of firing event as movedforward/backword first, then itemremoved next.
Merge pull request #1 from shosokawa/feature/calc_close

Made "itemremoved" event preventable