- updated MDC docs

- other related (but minor) fixes

- adding resource reading capability in IncludeFileAction (see bug 89)
  cleaning up IncludeFileActionTest.java
- other minor changes

"testResources" in pom.xml

constructor. Problem reported by Robert Christian in bug #85.

- fixed bug 78, in relation with failing caller data extraction (reported by Hans van der Meer)
- moved LoggingEventTest to test/

- fixed bug 90 by removing the outdated "configuration" section in chapter 2. 
  It was a duplicate of a homonym in chapter 3. 

See also http://www.qos.ch/pipermail/logback-user/2007-May/000216.html

- realigning with MDC as defined in SLF4J