Rename org.apache.logging.log4j.core.LogEvent.getMillis to getTimeMillis because “millis” is just a scale, but of what? Of the time stamp on the given event is what. The name makes sense compared to System.currentTimeMillis and org.apache.logging.log4j.core.helpers.Clock.currentTimeMillis() for example.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1593566 13f79535-47bb-0310-9956-ffa450edef68