Adding warning messages

git-svn-id: http://plugins.svn.wordpress.org/hyper-cache-extended/trunk@648411 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updating install docs and fixing typo

git-svn-id: http://plugins.svn.wordpress.org/hyper-cache-extended/trunk@923946 b8457f37-d9ea-0310-8a92-e5e31aec5664
Revert "Updating install docs and fixing typo"

This reverts commit f54b022cb227982d4128060510ebcaaa47eacf84.

git-svn-id: http://plugins.svn.wordpress.org/hyper-cache-extended/trunk@923947 b8457f37-d9ea-0310-8a92-e5e31aec5664