Twenty Fourteen: JavaScript fixes after running jshint, see r25960:

 * Enforce `===` instead of `==`
 * Fix confusing use of `!`
 * Remove unused variables like `calcNext`, defined but never used
 * Proper use of braces
 * Move functions out of if/else statements
 * Document unknown functions as Microsoft-specific
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git-svn-id: http://core.svn.wordpress.org/trunk@25928 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Explicitly globalize $is_nginx in vars.php.

props johnjamesjacoby.
fixes #25776.

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git-svn-id: http://core.svn.wordpress.org/trunk@25929 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Correct $user_id parameter description. props mauryaratan, Corphi. fixes #25774.
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git-svn-id: http://core.svn.wordpress.org/trunk@25930 1a063a9b-81f0-0310-95a4-ce76da25c4cd