Syntax updates for mod_s*.xml (sans mod_ssl.xml)

Cleanup effort in prep for GA push: Trim trailing whitespace... no func change

remove directive <compatiblity>s and add a module <compatibility>

Change the directives within the mod_session* modules to be valid both inside and outside the location/directory sections, as suggested by wrowe.

let subversion set the lastchangedrevision

mod_session_cookie: Add a session implementation capable of storing session information within cookies on the browser. Useful for high volume sites where server bound sessions are too resource intensive.