New dealer and router functions.
Corrected comments and declared static create_new_router_receiver and
create_new_dealer_sender functions
Deleted unused size variable (it was used with libzmq - new code uses
more straightfull libczmq bindings).
Now using dealer and router sockets and not taking into account buffers that
has 0 as size.
Debug message's place is better here (may be). Some comments about the
message variable that has been checked in get_json_message_id() function
and thus is safe to use in ENC_META_DATA: case.