Dashicons: Update to the latest dashicons files.

Merges [26925] to the 3.8 branch.

props empireoflight, melchoyce.
fixes #26518.

Built from https://develop.svn.wordpress.org/branches/3.8@26965


git-svn-id: http://core.svn.wordpress.org/branches/3.8@26844 1a063a9b-81f0-0310-95a4-ce76da25c4cd