Bug fix: prevents verse_server for load 1, when WebSocket is used.
 
 - It is neccessary to set read/write set of socket descriptors only
   in situation, when WSLay has something to receive/send.
 - Small refactoring
 - More debug prints.

Signed-off-by: Jiri Hnidek <jiri.hnidek@tul.cz>