The role of a slave as a host for Factorio servers is not well reflected
in its name and has caused confusion among users. Rename slave to host
to better reflect its role as a host of Factorio servers.
The role of the master server as the party controlling every part of the
cluster is not well reflected in its name and has caused confusion among
users on several occasions. Rename master to controller to better
reflects its role.
The interface provided by Winston is unusably slow for querying large
logs. Reimplement the log querying with both forwards and backwards
line reading and a simple file based index to skip files which do not
contain any lines matching the filter.