Deprecate custom dom events

### View events with corresponding model events

The following events will now be deprecated when calling `.on` on these views.

#### WorkspaceView (atom.workspaceView)

* cursor:moved
* pane:active-item-changed
* pane:became-active
* pane:became-inactive
* pane:item-added
* pane:item-moved
* pane:item-removed
* pane:removed
* pane-container:active-pane-item-changed
* selection:changed
* uri-opened

#### EditorView

* cursor:moved
* selection:changed

#### PaneView

* cursor:moved
* pane:active-item-changed
* pane:became-active
* pane:became-inactive
* pane:item-added
* pane:item-moved
* pane:item-removed
* pane:removed
* selection:changed

### Remaining custom view events

#### EditorView

* editor:attached
* editor:detached
* editor:display-updated
* editor:will-be-removed

### PaneView

* pane:attached
* pane:active-item-title-changed
* pane:active-item-modified-status-changed