Update README.md
added auth support to builder.py
added world.py so server can know default world

not used in the server yet
fix for linux
send client original block if action not allowed
support local config file in server
default chunk caching in server
more server-side validation
removed on_nick
login when token is installed
added help topics to server
server performance improvement
only send non-default blocks on initial chunk request?
added help for /pq command
reformatted server help
revert world check in on_chunk
another server check
removed unneeded lines
Merge branch 'master' into exe