web server/bots improvements

- bots negotiate TTYPE of xterm-256color to avoid 'python internal curses bug' warning
- web server is now completely decoupled from message server
- web server is 100% modular
  - webmodules/* for engine-level modules
  - default/webmodules/* for overrides and custom modules
https://github.com/haliphax/x84/blob/master/x84/msgpoll.py#L180

It's used in expanding the path for "datapath" ... though if that's already handled before it's written to default.ini, I suppose it's unnecessary. Let me know what you think.