RFE: Add API to activate waypoint or waypoint within route

[antipole2]

As I understand it, there is no plugin API enabling a plugin to activate a route.
A year or so ago I made a request in FlySpray but this fell by the wayside.

Now @wbijen has made the case for such an ability - see here.
I think there could be other applications for this and I wou;d be willing to support it in the JavaScript plugin.

It would require the ability to activate a route at a given waypoint.
Advancing the waypoint could be covered by just activating at the next one, although might this lose route progress information?
There should be the ability to deactivate a route - maybe activate the route with a zero GUID for the waypoint?

The special case of activating a waypoint not in a route is covered because OCPN actually creates a one-step GOTO route for this.

[leamas]

It's a bit convoluted from a plugin perspective, but if you really want to activate a route it's supported in the REST API documented in rest_server.h