Moved Skin::makeGlobalVariablesScript() to OutputPage::getJSVars()

Moved Skin::makeGlobalVariablesScript() to OutputPage::getJSVars()
* merged <script> and if ( window.mediaWiki ) block with the one of mediaWiki.loader as stated in the doc
* removed dependency of $wgTitle
* the two only calls to this functions are in SemanticForms, but will not affect current version of MediaWiki:
** specials/SF_UploadWindow.php: this file is only used before 1.16
** specials/SF_UploadWindow2.php: the call is part of the else branch of a "method_exists( $wgOut, 'addModules' )" check, which means it's not called since 1.17