Allow columns on manage pages to be hidden

[ryan]

Much in the fashion of the metabox hiding, allow columns on the manage pages to be hidden. If you don't use Categories, hide them.

Show hide for posts page. Inline edit not yet hidden column aware.

With inline edit support

(In [8858]) Column hiding for manage posts. see #7725

Committed for wider testing. Need to consolidate some of those CSS classes and do this for pages, links, comments, etc.

(In [8860]) Column hiding for pages. see #7725

(In [8888]) Column hiding for links. see #7725

(In [8894]) Column hiding for media library. see #7725

(In [8923]) Consolidate column header code. Add column hiding to taxonomy pages (incomplete). see #7725

(In [8930]) Column hiding for tags. see #7725

(In [8932]) Column hiding for categories. see #7725

(In [8933]) Column hiding for link categories. see #7725

(In [8936]) Column hiding for users. see #7725

Column hiding for comments, has CSS issues (see reply)

There's my shot at column hiding for edit-comments.php. I moved the JS for the "Advanced Settings" box to it's own file to avoid duplicating that JS all over the place.

There is one issue with my patch though: due to the generic CSS classes that are now added to the columns, the "Comment" column is a bit screwy. The links are the wrong color and I think there's an issue with the width of the column. Someone with better CSS skills than I will need to debug it.

Use edit-comments.js instead of new comments file + include settings-box.js file

Link colors fixed, but I can't figure out the column width issues (hide "Submitted" column to see)

(In [8988]) Column hiding for comments. Settings box JS consolidation. Props Viper007Bond. see #7725