auto-fade the new tree message

[arlin]

When a tree is displayed, there is a message like the one below. To make the message disappear, the user must click the "X".

The message will reappear if the user switches to a different version of the tree (scaled version) and then switches back. This behavior makes the first behavior more annoying.

To do:

• Don't require the user to dismiss the notice. Make it fade away automatically in 5 seconds. The number of tips is still visible in the tree-version chooser.
• Dismiss the notice permanently. Don't re-display it when the tree version is selected again.

[arlin]

@ducvan0212, I think you fixed this in dev, right? If so, then close it.

[ducvan0212]

Yes, I did. Closed this issue.