Database updates for Improved Threaded
Fix js to use with new Improved Threaded

removed unneeded functions from collapsible_comments.js.  Added
wgxpath_install.js to let IE have xpath.
Update to remove D2 and add Imp Thread

Remove all D2 stuff and setup new Improved Thereaded comment mode to
work with collapsable comments
Updated to CSS

Remove D2 and add changes needed for Improved Threaded comments.
Update to add new js file
Remove D2 and add new theme support
Merge pull request #171 from paulej72/collapsible_comments

Rework collapsible comments to use CSS, work on Improved Threading view.