Allow forced shutdown of Confluence by configuring CATALINA_PID in standalone distribution

This is a request to include the work around from http://confluence.atlassian.com/display/CONFKB/Confluence+Does+Not+Terminate+after+Shutdown+Script (adding $CATALINA_PID) as part of our setenv.sh

$CATALINA_PID in setenv.sh is not a default setting in Tomcat, but perhaps it's something that we can consider for Confluence standalone?

At the moment the challenge is to identify which directory that Tomcat can write to and know what the pid is for Confluence. Matt R mentioned that perhaps we can let Tomcat write to its /temp folder.