propertyControl now handles several different property types,
based on the thing description. This reduces duplication and
should keep the code cleaner.
In the future this will become a part of a labthings-vue package,
I hope!
I had intended to store a ConsumedThing for each Thing, in
a module in the store. Until that is possible (will require some
more attention to dependency management) I will just store
the TDs instead.
This commit includes a lot of the code I wrote for node-wot use,
but without any dependence on node-wot.
