Added events for editor

Signed-off-by: Slava Zanko <slavazanko@gmail.com>
Add placeholder for return values from any of event handler.

Signed-off-by: Slava Zanko <slavazanko@gmail.com>
Added events for Treeview

Signed-off-by: Slava Zanko <slavazanko@gmail.com>
Added new keymap implementation

Signed-off-by: Slava Zanko <slavazanko@gmail.com>
Add events for filemanager.

Signed-off-by: Slava Zanko <slavazanko@gmail.com>
Add events for core (incomplete yet)

Signed-off-by: Slava Zanko <slavazanko@gmail.com>