Update jquery.webfonts from upstream

Upstream: https://github.com/wikimedia/jquery.webfonts/

Changes:
* Respect explicit font styles of child elements when switching
languages
* Fix duplicate font-weight property

Change-Id: Ic45357b2613e6f33c392f9a78cc389f31c99e036

lib/jquery.webfonts.js

@@ -61,8 +61,10 @@
 		 * @return {String} Font family name
 		 */
 		getFont: function( language ) {
+			language = ( language || this.language ).toLowerCase();
+
 			if ( this.options.fontSelector ) {
-				return this.options.fontSelector( this.repository, language || this.language );
+				return this.options.fontSelector( this.repository, language );
 			} else {
 				return this.repository.defaultFont( language );
 			}
@@ -211,7 +213,15 @@
 
 				// Load and apply fonts for other language tagged elements (batched)
 				if ( element.lang && element.lang !== webfonts.language ) {
+					// language differs. We may want to apply a different font.
+					if ( webfonts.hasExplicitFontStyle ( $element ) ) {
+						// respect the explicit font family style. Do not override.
+						// This style may be from css, inheritance, or even from
+						// browser settings.
+						return;
+					} else {
 						fontFamily = webfonts.getFont( element.lang );
+					}
 
 					if ( !fontFamily ) {
 						// No font preference for the language.
@@ -246,6 +256,24 @@
 			} );
 		},
 
+		/**
+		 * Find out whether an element has explicit non generic font family style
+		 * For the practical purpose we check whether font is same as top element
+		 * or having any of generic font family
+		 * http://www.w3.org/TR/CSS2/fonts.html#generic-font-families
+		 * @param {jQuery} $element
+		 * @return {boolean}
+		 */
+		hasExplicitFontStyle: function ( $element ) {
+			var elementFontFamily = $element.css( 'fontFamily' );
+
+			// whether the font is inherited from top element to which plugin applied
+			return this.$element.css( 'fontFamily' ) !== elementFontFamily
+				// whether the element has generic font family
+				&& ( $.inArray( elementFontFamily,
+					['monospace', 'serif', 'cursive','fantasy', 'sans-serif'] ) < 0 );
+		},
+
 		/**
 		 * List all fonts for the given language
 		 *
@@ -375,10 +403,6 @@
 				fontFaceRule += '\tfont-weight:' + fontconfig.fontweight + ';';
 			}
 
-			if ( fontconfig.fontweight !== undefined ) {
-				fontFaceRule += '\tfont-weight:' + fontconfig.fontweight + ';';
-			}
-
 			if ( fontconfig.fontstyle !== undefined ) {
 				fontFaceRule += '\tfont-style:' + fontconfig.fontstyle + ';';
 			} else {