Bundled up changes

Major changes:
  * replace linked lists with hashtables where it makes sense
  * add server password support
  * segmentation fault fixes
  * mod_ctcp changed to mod_base for basic functions that need not be in
    the core (and useless fun stuff)

Minor changes:
  * don't cast malloc() return value
  * remove unused code
  * add helpers for some common commands
  * change some defaults