• Synopsis shows code samples in Log4perl.pm/README
  
• Slight Log4j incompatibility but useful: %F{n} lets you
  limit the number of entries the source file path is logged
  
• Erik W. Selberg (erik@selberg.com) suggested having PatternLayout.pm
  suppress another \n if the messages already contains a \n and the
  format requires a %n. Done.
  
• Erik W. Selberg (erik@selberg.com) suggested loggers should take
  any number of messages and concatenate them. Done.
  
• Fixed double-init problem and added a test case. Now the entire
  configuration is cleared before the second init(). However, this
  surfaced a problem with init_and_watch: If a program obtains
  references to one or more loggers, rewriting the configuration
  file during program execution and re-initing makes these reference
  point to loggers which hold obsolete configurations. Fixed that by
  code in debug(), info(), etc. which replaces (shudder) the
  logger reference the program hands in to them with a new one of
  the same category. This happens every time if 'init_and_watch' has
  been enabled. However, this introduces a small runtime penalty.
  This is different from the original log4j, which does some
  half-assed re-initialization, because Java isn't expressive enough
  to allow for it. Making this thread-safe might be tough, though.
  
• Added DEBUG statements to Logger.pm and Config.pm to trace execution
  (debugging won't work because of "eval"s). Both files define a
  constant named DEBUG towards the top of the file, which will
  have perl optimize away the debug statements in case it's set to 0.
  
• A warning is issued now (once) if init() hasn't been called or
  no appenders have been defined.
  
• Added ':levels' target to Log::Log4perl to import $DEBUG, $ERROR,
  etc. levels (just like 'use Log::Log4perl::Level' works).
  
• Added ':easy' target to allow for simple setup
  
• Code references can be passed in as log messages to avoid parameter
  passing penalty