Consistently use $wp_rewrite->index instead of hardcoding "index.php".

props wonderboymusic. fixes #7337

git-svn-id: http://core.svn.wordpress.org/trunk@23305 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Update the copyright notice to 2013. Yes — WordPress turns *10* this year.

props kraftbj. fixes #22987

git-svn-id: http://core.svn.wordpress.org/trunk@23306 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Properly wipe capabilities from new site-independent multisite users by using the right key.

props wonderboymusic. fixes #15627

git-svn-id: http://core.svn.wordpress.org/trunk@23307 1a063a9b-81f0-0310-95a4-ce76da25c4cd