Category excluding filter.

This filtering appender allows you to choose some category
names that won't be logged to the delegated appender. This
is useful if you have e.g. a category that you use to log
web requests to one file, but want to keep those entries
out of the main log file without having to explicitly list
all the other categories that you _do_ want to include.

Has one option, "exclude", which is a category name or
array of category names. The child appender is set in
"appender", modelled on the logLevelFilter.
improved coverage of gelf appender
improved coverage of rolling file stream
improved coverage of lib/log4js.js
improved coverage of hookio appender
improved coverage of date format
Merge pull request #140 from karlvlam/master

Add custom field support to GELF appender
Merge branch 'master' of https://github.com/nomiddlename/log4js-node

Conflicts:
	test/gelfAppender-test.js
removed check on undefined configState.filename - should not happen, and is covered by the statSync anyway
simplified the reload config code a little, moved the tests into their own file, improved coverage
Getting console appender to work with node-webkit
Merge pull request #142 from crisply/master

Allows use of Console Appender when using with node-webkit
0.6.7
Merge pull request #119 from UniversityofWarwick/category-filter

Category excluding filter.
Merge branch 'master' of https://github.com/nomiddlename/log4js-node
formatting fixes, unnecessary code removed
Clustered appender for log4js.

+ lib/appenders/clustered.js
+ test/clusteredAppender-test.js

Instead os using sockets (like multiprocess) or dead and unmaintained hook.io, Clustered appender
uses process.send(message) / worker.on('message', callback) mechanisms for transporting data
between worker processes and master logger.

Master logger takes an "appenders" array of actual appenders that are triggered when worker appenders send some data.
This guarantees sequential writes to appenders, so the log messages are not mixed in single lines of log.
Merge pull request #149 from mkielar/master

Clustered appender for log4js.
Update layouts.js
Update date_format.js