Add a guide to Apache 1.3.21 changes, taken from the commit logs so not

Add a guide to Apache 1.3.21 changes, taken from the commit logs so not
to miss things in CHANGES and sorted into categories, with minor changes
lumped together and some explanations changed to be more readable.
PR:
Obtained from:
Submitted by: Mark Cox
Reviewed by: Several Red Hat Apache Week team members

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@91261 13f79535-47bb-0310-9956-ffa450edef68