Only show badge when status has changed

[tellyworth]

We should only show the comment status badge when the status has changed (i.e. "user spammed this comment").

For comments that don't have the badge, a hover link to access the history is more consistent with the current WP UI.

[josephscott]

(In [323236]) Only show the status badge if the comment status has been changed by someone/something other than Akismet

Show a 'History' link in the row-actions

fixes #1251

[tellyworth]

additional patch to restyle the badge

[tellyworth]

Fix WP 3.0 issues in earlier patch