Some rewording and other improvements

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1629867 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=43682
Add support for referring to the current context, host and service name in per Context logging.properties files

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1629871 13f79535-47bb-0310-9956-ffa450edef68