various refactorings of the message network

- derived database names are automatic
  (simpler configuration, documented) **
  this is important, could break folk! **
- make config option poll_interval optional
- make config option addr, port optional
- make cipher_list configurable (optional)

- make very clear, when obscure errors occur
  in CherryPy(cert_file) calls, the offending
  file path, to make it easier for folk to know
  where they went wrong.

- allow msgpoll.py and webserve.py to be executed
  independently of x/84
- distinguish managed vs. unmanaged server start
  in engine.py

- remove various redundant log instantiations
- some function juggling for brevity and to make
  common with similar "unmanaged" servers
- make use of get_ini() in various places, removes
  the hard work of map(str.strip, stuff)
- document self-signing cert generation
- assert URL route mappings exist at start-time
`KeyError: 'tag'` and the same below.