Many more changes.
Cleaned up the files -- rearranging submodule css in groups.
Added pure-menu-hidden to be able to explicitly control opening and closing menus.
Default menu state is now visible, so use pure-menu-hidden to hide.
Removed pure-menu-open -- redundant with pure-menu-hidden (testing this...)
Ensured that pure-menu. always prefixes submodules to ensure  that pure-menu defaults are overriden.
Added comments (usually prefixed with EAP) to help explain the reasoning behind things.
This is NOT ready for consumption yet -- and would break current menus badly.
Fixed selected state.
Next - skinning.