Name notification server threads

It allows to read name of thread during debugging, so we know in thread of which node we are. Also it can provide better error description, when name of problematic thread will be printed.

So it changes this:

to this:

It conflicts with !107 (merged), so I rebased it on top if this. If you want to avoid conflicts, merge these two merge requests close to each other :)

Please review: @kmochocki @mzebrak