Cursor DOM events

[streamich]

• [x] Keyboard movement
  • [x] ArrowLeft
  • [x] ArrowRight
  • [x] ArrowUp
  • [x] ArrowDown
  • [x] Shift + ArrowLeft
  • [x] Shift + ArrowRight
• [x] Mouse movement
  • [x] Single click
  • [x] Double click
  • [x] Triple click
  • [x] Quadruple click
• [x] Shortcuts
  • [x] Ctrl + A: select all
  • [ ] Ctrl + X: cut line if caret cursor
• [x] Multiple cursors
  • [x] Option + Click: add a new cursor
  • [x] Keyboard movement for all cursors
• [ ] Blur and focus
  • [x] Ability to remove all cursors.
  • [x] Blur all cursors, when editor loses focus.
  • [ ] Focus all cursors, when editor regains focus.
    • [ ] Insert a cursor on focus, if no cursors set?