Truncate map and layer names if they are too long to fit side panel.

[cynthiamah]

Make long map names and long layer names have the same behavior as long item names.

Map names and layer names should be truncated with ... appended to the end to indicate more text that is not displayed.

Wishlist - would be nice when hovering over truncated map and layer names to have a tooltip with the complete name. (See Google My Maps)

[vanwars]

This should literally take 1 minute to do.

[gitriley]

See PR #235