Make some parts of logger and console thread-safe.
Simplify console: remove special commands; remove prefix for script
commands.
Remove LOG_ONCE, to simplify logger.
Change some code to use the new logger interface.
Fix OOS when revealing map.
Clean up some formatting.
This was SVN commit r8511.
Support asynchronous path queries.
Allow escaping when stuck in impassable terrain tiles.
Split Update message in multiple phases, to cope with ordering
requirements.
Support automatic walk/run animation switching.
This was SVN commit r8058.