Remove jquery.i18n code that the ULS extension overrides

Instead of using the whole jquery.i18n code, use only required parts
that are not customized in MW ULS. For this define a new RL module
ext.uls.i18n.

Also refactor MW message store for jquery.i18n.

Change-Id: Idda9fe505428ade409d937314d7216ebb4232c36

resources/js/ext.uls.i18n.js

@@ -0,0 +1,70 @@
+/**
+ * ULS i18n preparation using jquery.i18n library
+ *
+ * Copyright (C) 2012-2013 Alolita Sharma, Amir Aharoni, Arun Ganesh, Brandon Harris,
+ * Niklas Laxström, Pau Giner, Santhosh Thottingal, Siebrand Mazeland and other
+ * contributors. See CREDITS for a list.
+ *
+ * UniversalLanguageSelector is dual licensed GPLv2 or later and MIT. You don't
+ * have to do anything special to choose one license or the other and you don't
+ * have to notify anyone which license you are using. You are free to use
+ * UniversalLanguageSelector in commercial projects as long as the copyright
+ * header is left intact. See files GPL-LICENSE and MIT-LICENSE for details.
+ *
+ * @file
+ * @ingroup Extensions
+ * @licence GNU General Public Licence 2.0 or later
+ * @licence MIT License
+ */
+
+( function ( $, mw, undefined ) {
+	'use strict';
+
+	// jquery.i18n has CLDRPluralRuleParser but MediaWiki also has the same
+	// parser. Reuse it by aliasing it to window.pluralRuleParser
+	window.pluralRuleParser = mw.libs.pluralRuleParser;
+
+	/**
+	 * jquery.i18n message store for MediaWiki
+	 *
+	 */
+	var MWMessageStore = function () {
+		this.messages = {};
+	};
+
+	MWMessageStore.prototype = {
+		init: function () {},
+
+		get: function ( locale, messageKey ) {
+			return ( this.isLoaded( locale ) && this.messages[locale][messageKey] ) ||
+				'<' + messageKey + '>';
+		},
+
+		set: function( locale, messages ) {
+			this.messages[locale] = messages;
+		},
+
+		isLoaded: function ( locale ) {
+			return this.messages[locale];
+		},
+
+		load: function ( locale ) {
+			var store = this,
+				deferred = $.Deferred(),
+				url = mw.util.wikiScript( 'api' ) + '?action=ulslocalization&language=';
+
+			if ( store.isLoaded( locale ) ) {
+				return deferred.resolve();
+			}
+
+			deferred = $.getJSON( url + locale ).done( function ( data ) {
+				store.set( locale, data );
+			} ).fail( function ( jqxhr, settings, exception ) {
+				mw.log( 'Error in loading messages from ' + url + ' Exception: ' + exception );
+			} );
+			return deferred.promise();
+		}
+	};
+	mw.uls = mw.uls || {};
+	mw.uls.messageStore = new MWMessageStore();
+}( jQuery, mediaWiki ) );