Added a sleep before starting Sevabot to avoid skype.Attach() failing

Other minor fixes
 - Added variables for the username and X server display number
 - Added some indents
 - Similar fixes on `start-vnc.sh'
Added `LOG_LEVEL' variable for setting

`LOG_LEVEL' can be either 'INFO' or 'DEBUG'.
This variable overrides `--verbose' option.
Added a customizable message handler framework

Now you can easily add built-in commands and other advanced
handlers by defining handler classes.
Also added a built-in command for calling.

Other minor fixes
 - Stopped using `shlex' to parse commands because
   msg.Chat.Body.encode('utf-8') seems to fail on some languages
   e.g. Japanese.
Added a fancy dice roll module
Made getting LOG_LEVEL setting simpler
Made sure that split words are decoded before use

Now use `shlex` to split a message into words.
Added base class for message handlers

All message handlers must inherit `HandlerBase`.
Users should put custom handlers in `custom_handlers.py`.
Merge pull request #37 from builtinnya/develop

Various fixes and improves