Right click to select path length

[snip]

For now, right click on a glider label display history path of the day.
It may be interesting to keep this feature but also if right clicking again, we can switch to 5' history, 10' history and then no history.

This will also allow to show path of a given glider and to erase it without reloading all the page.

[snip]

As a workaround, to erase path of a selected glider we can double click on its color square in the list of gliders.