`WP_Query` was only missing one access modifier.

Add access modifier (`public`) to applicable class methods/members of `WP_Rewrite`. I am not brave enough to set some of the `var`s to `private` without more testing.

See #27881, #22234.

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git-svn-id: http://core.svn.wordpress.org/trunk@28359 1a063a9b-81f0-0310-95a4-ce76da25c4cd