Adds css columns to tag list and moves show button
Improve tag show/hide button appearance

This works well with the browsers that can handle the multi-column, but
looks dorky with IE 7 & 8.
Merge remote-tracking branch 'upstream/1.5.x' into 1.5.x

Conflicts:
	includes/css/screen.css
	includes/scss/screen.scss
Improve "show more tags" appearance in old IE

Slight de-dorkification for users of IE8 and IE7.
Clean up

Remove commented-out code.
Merge pull request #375 from dcavins/tag-link-part-2

Improve new tag list view for IE7 & 8 users