Improve the behaviour of the tool panel

[qqnluaq]

For mobile applications, be able to use a swipe gesture to expand and collapse a panel.

If the panel has content "below the fold", show an indicator that scrolling is possible.

Restyle the panel messages as a popup, that automatically hides after a couple of seconds.

Associate linked panels together as a group, with a way to get notification when any panel of the group is (de-)activated.

The menu tool is converted to a tabbed panel container.

The HTML and CSS for panels is to be restructured to make re-skinning easier.

This is a feature added for WFONE app, and the implementation is contained in
https://github.com/qqnluaq/smk-client/tree/feature/wfone