Parameter bulk read

I tried to rework the parameter view loading of values. Now the parameter view handler creates a queue and a thread which calls getItem for every item and fills the queue with the responses as they are returned. The queue is stored in the session. A new handler /getitem/ gets the queue from the session and empties it and returns the data retrieved so far, so it has to be called repeatedly until all values are read. With this scheme only a handful of /getparams/ calls are needed to retrieve all data. I got it to work with the old layout, not really sure how to move it to the newest, could you have a look?
(never did a pull request on github before, hopefully it makes sense)