Player title colors and descriptions for WebTiles lobby and chat

This gives player names a color and tooltip description in the lobby
and spectator list based on the following "titles":

  admins:         Server Administrator
  devteam:        DCSS Developer
  goodplayers:    a player with 10+ wins
  greatplayers:   a player that has won every species in a version of
                  crawl
  greaterplayers: A greatplayer has won every species and class in a
                  version of crawl
  centuryplayers: A greaterplayer that has 100+ wins

The admins are set in the server configuration file option
server_admins. The devteam members are stored in the file
devteam_crawl_accounts.txt in the webserver folder, which is then read
by the WebTiles server when configuration is loaded. This file must be
updated in the repository when changes occur.

The script webserver/get_titles.py fetches the nickdb from the public
Sequell URL and extracts the player titles to a file. It then sends a
SIGUSR2 signal to the WebTiles server, which causes the server to
reload this data. This script is meant to be run regularly via
e.g. cron, and probably needs updating to only change the file and
send the signal if the title listings have changed.
Don't use ids, and don't crash the server if devteam_file is not set.