WMS parser and Promise handling temporarily broke various layer functionalities about shire HOT 2 CLOSED

Expectedly, after 4dfba94 also many more layer functionalities have stopped working.

First thing I want to try is testing the integration of walkermatt/ol-layerswitcher to:

1. List layers automatically also in OL map
2. Turning on/off layer functionality comes back working

If everything works, I might think on implementing the layerswitcher and the Turbo87/sidebar-v2 (see walkermatt/ol-layerswitcher#67).

from shire.

First successfully integration of the ol-layerswitcher (1e98b9d).
I need to:

• - get the other functionalities back to work (a first test shows that popup might still work)
• - try to integrate the layerswitcher with the sidebar (maybe splitting operational and basemap layers) (waiting for PR decision walkermatt/ol-layerswitcher#76)

from shire.