Eliminate the 1px padding adjustment on active buttons because it creates an un-clickable dead zone 1px high and spanning the entire width of the button.

Merges half of [26993] to the 3.8 branch.

props johnbillion.
see #26700.

Built from https://develop.svn.wordpress.org/branches/3.8@26998


git-svn-id: http://core.svn.wordpress.org/branches/3.8@26875 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Dashboard widgets: Don't link to Pages or Posts for Authors or Contributors respectively.

Merges [26999] to the 3.8 branch.

props mattheu.
fixes #26574.

Built from https://develop.svn.wordpress.org/branches/3.8@27001


git-svn-id: http://core.svn.wordpress.org/branches/3.8@26878 1a063a9b-81f0-0310-95a4-ce76da25c4cd
3.8.1-beta1

Built from https://develop.svn.wordpress.org/branches/3.8@27002


git-svn-id: http://core.svn.wordpress.org/branches/3.8@26879 1a063a9b-81f0-0310-95a4-ce76da25c4cd