[LOG4J2-293] Changed the ConfigurationFactory to recognize and properly use the classpath: URI scheme in addition to the classloader: URI scheme. Thanks to Abhinav Shah for the patch this change was based on.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1519217 13f79535-47bb-0310-9956-ffa450edef68