Whitespace fix before beginning work.

Cleaning up the whitespace in the file before making major changes, to facilitate clean refactoring.
Switching to markers.

Previous there were a series of static final booleans to determine
what to log.  In logback this sort of filtering and annotation is
handled using Markers, so now instead of checking the static boolean,
the code passes the marker it wants to use.
Adding logback configuration file.

Disabling debug logging by default.
Updating logging in EpidemicServer.

Using "{}" template syntax rather than building strings at runtime.
Merging in master.
Merge pull request #44 from dclements/epidemic_logging

Logging update for EpidemicServer