WebGL viewer improvements

[sliptonic]

The 3D web model viewer overlay should be reworked to improve user experience.

• [ ] The very large title '3D web models viewer' is unnecessary.
• [ ] The copyright statement can be moved to the bottom and reduced in size.
• [ ] The instructions on usage should be moved to a tooltip or bottom so that the tree is at the top and easily accessed

Clicking items in the tree has two different results and this can be confusing. If the item is a group parent, clicking it expands or collapses the node. If it is a single item, clicking it hides/shows the item. I suggest that each row in the tree have an eyeball icon which controls the hiding/showing function. Clicking would be reserved to selection.