remove cdm tiles; update cdm stylesheet as to stop reading on yellow
further tweak expanded cdm display
Merge pull request #100 from yanobs/master

 Check that $_SESSION["uid"] is defined before checking value
cdm expanded: add some box shadows
fix stuff broken by previous pull
fix cdmExpandArticle not always removing active class; make moving between posts take expanded cdm margins into account
set combined display mode as default
attachment dropdown: limit width, set top margin
make prefs footer version respect HIDE_VERSION
keep cdm expanded articles white
toggleUnread: remove scriptaculous highlight