Some commands were causing a freeze when there was a trailing space
in the command line.
* The current ssl_verify value is used in /connect (no need to restart
mcabber)
* System messages are not blocked anymore when the option
"block_unsubscribed" is set
* Do not enter chat mode after command "/del" or when somebody joins a room
* Display mcabber version in the status window (when chat mode is disabled)
(Suggested by pmw & hednod)
* Small code cleanup and a few cosmetic changes
