Remove redundant esc_url() call. props pauldewouters. fixes #23643.

git-svn-id: https://core.svn.wordpress.org/trunk@23553 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revert 23416, 23419, 23445 except for wp_reset_vars() changes. We are going a different direction with the slashing cleanup, so resetting to a clean slate. see #21767


git-svn-id: https://core.svn.wordpress.org/trunk@23554 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Introduce wp_slash() and wp_unslash(). This will be used to cleanup the myriad calls to addslashes*, add_magic_quotes, stripslashes*. see #21767


git-svn-id: https://core.svn.wordpress.org/trunk@23555 1a063a9b-81f0-0310-95a4-ce76da25c4cd