add several IRC connecting options

HUBOT_IRC_NICK     nick      - the nickname you want to register as
HUBOT_IRC_USER     user      - your username
HUBOT_IRC_REALNAME real      - your realname
HUBOT_IRC_PASSWORD password  - the server password
                   timeout   - the TCP connect timeout
Merge branch '#32-irc-connect-options'
check pkg before using `$irc->enable_ssl`;
Merge branch '#33-enable-ssl-warnings'
bumpup to v0.1.6