Add an empty WEB-INF/classes dir to the WAR for testing WebappClassLoader.getURLs()

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1526214 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55383
Improve HTML markup of the ErrorReportValve.
The design/layout is still the same, but I'm looking into how it can be improved.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1526224 13f79535-47bb-0310-9956-ffa450edef68
Fix indent

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1526233 13f79535-47bb-0310-9956-ffa450edef68