Upd: Start answetimer feature.

AnswerTimer class added to podiapanel.
Upd: Work so far

DO NOT RUN FROM THIS COMMIT. App not in working order. Podiapanel is a
mess, so I'm going to work on improving it in another branch before
returning to work here.
Add: Timer image

Also updated resmaps accordingly.
Bug fix: ANSWER_TIMEOUT event in main

Main now accepts and properly deals with ANSWER_TIMEOUT events.
Add: Podium, AnswerTimer, Score, Highlight

These classes implement all the podia functionality to be used in
rewritten podiapanel.py (which is forthcoming). These are much better
modularized and decoupled than the old podiapanel.
Upd: Rewritten podiapanel and answer timeouts

Answer timeouts fully implemented; podiapanel rewrite complete.
Docs: Typo fix in readme
Bug fix: Uncomment intro lines in main

Forgot to uncomment these while testing for this branch.
Upd: Moved answer time limit constant

ANSWER_TIME_MS moved to root config.py. Though strictly ui-related, it
counts as a general game setting a typical user would likely want to
change, so it will be easier to find in this module.
Docs update: Readme terms "player" vs. "team"

Readme now consistently uses "player" to refer to a participant. This is
consistent with the terminology used throughout the code.
Docs: Updated to include timeout functionality.