All data items now get their `item.treeList` api added even if deferBuild is set.
This means the apis can be used regardless of whether the tree has built their
ui pieces.
Also adds a number of new api calls
Top-level methods:
- clearSelection - clears selection from the list
- filter(filterFunc) - filters the tree using the provided function
Data item functions:
- item.treeList.sortChildren(sortFunction)
- item.treeList.replaceElement(element)
This introduces a much more consistent set of events within the editor
for whenever a element is added, removed or modified.
The events emited on the `RED.events` event system. The event names
take the form: `"<thing>:<action>"`.
`<thing>` can be one of:
- nodes
- flows
- subflows
- groups
- links
`<action>` can be one of:
- add
- remove
- change
The payload of the events is the object in question.
There is also:
- flows:reorder - when tabs are reordered. Payload is array of flow ids.
- workspace:clear - when the workspace is emptied - part of switching projects
The `nodes:change` event was already used by RED.nodes.dirty() to cause
the Deploy button to become active. This renames that event to:
- workspace:dirty - Payload is boolean flag for the dirty state
This commit also updates the Palette to use the subflows:change event to
only redraw subflows that have actually changed rather than refresh them
all whenever one of them *might* have changed. This removes a noticable
flicker of the icon which was needlessly being redrawn.
This moves the expensive redraw code out of the event handling phase
and onto the browser's repaint phase. This makes the event handling
more responsive, particularly when dragging a large number of nodes.
It also removes lots of unnecessary anonymous functions in the redraw
code that should also improve performance.
