Task/499 network part of issue

### Description
o Fixed the 'network part' of issue #499 (part 1 of uncached queries/updates for context providers).

o About adding CB_PORT as preferred variable to BROKER_PORT, doing the FULL change, i.e. completely stop using BROKER_PORT etc is a too big task to include in this PR. I tried but it got BIG. Coming in a PR soon.

o About statistics, I have passed completely on the statistics in this PR. There are two new messages 'QueryContextResponse' and 'UpdateContextResponse' but they are NOT included in the statistics. Perhaps this was not a good idea, and it is easy enough to include them. However, I have a feeling the entire statistics concept needs to be looked over ...

o I had some problems with the compiler copying entire vectors, in the clone/fill functions. I changed a few of them from 'const Class&' to 'Class*'. Also, I changed the name 'clone' to 'fill' for the methods that don't actually clone anything (methods that just fill).

...and mark (if it doesn't involve too much work) all the points in this file in which unification has to be done with a FIXME referencing the new issue.