Add instrument editors to instrument library editor

Now that the UI of the instrument editors is updated to the new UI style and also updated to the internal usage structures, these instrument editors can be used in the instrument library editor to modify an instrument's content.

So far only the name and the description could be edited, and this only with a quite poor dialog. Now this poor dialog got obsolete, and all of the instrument's data can be edited with the nice new UI as in the instrument view itself.