Landing the new expando management code. Completely overhauls how data is associated with elements.

Plugins will be most interested in:
- jQuery.data(elem) -> Unique ID for the element
- jQuery.data(elem, name) -> Named data store for the element
- jQuery.data(elem, name, value) -> Saves a value to the named data store
- jQuery.removeData(elem) -> Remove the expando and the complete data store
- jQuery.removeData(elem, name) -> Removes just this one named data store

jQuery's .remove() and .empty() automatically clean up after themselves. Once an element leaves a DOM document their events are no longer intact. Thus, statements like so:
{{{
  $("#foo").remove().appendTo("#bar");
}}}
should be written like so:
{{{
  $("#foo").appendTo("#bar");
}}}
in order to avoid losing the bound events.

src/core.js

@@ -238,7 +238,7 @@ jQuery.fn = jQuery.prototype = {
 			var clone = ret.find("*").andSelf();
 
 			this.find("*").andSelf().each(function(i) {
-				var events = this.$events;
+				var events = jQuery.data(this, "events");
 				for ( var type in events )
 					for ( var handler in events[type] )
 						jQuery.event.add(clone[i], type, events[type][handler], events[type][handler].data);
@@ -411,6 +411,8 @@ jQuery.extend = jQuery.fn.extend = function() {
 				if ( target == prop[i] )
 					continue;
 
+				// Recurse if we're merging object values
+				if ( deep && typeof prop[i] == 'object' && target[i] )
 					jQuery.extend( target[i], prop[i] );
 
 				// Don't bring in undefined values
@@ -450,6 +452,58 @@ jQuery.extend({
 	globalEval: function( data ) {
 		data = jQuery.trim( data );
 		if ( data ) {
+			if ( window.execScript )
+				window.execScript( data );
+			else if ( jQuery.browser.safari )
+				// safari doesn't provide a synchronous global eval
+				window.setTimeout( data, 0 );
+			else
+				eval.call( window, data );
+		}
+	},
+
+	nodeName: function( elem, name ) {
+		return elem.nodeName && elem.nodeName.toUpperCase() == name.toUpperCase();
+	},
+	
+	cache: {},
+	
+	data: function( elem, name, data ) {
+		var id = elem[ expando ];
+
+		// Compute a unique ID for the element
+		if ( !id ) 
+			id = elem[ expando ] = ++uuid;
+
+		// Only generate the data cache if we're
+		// trying to access or manipulate it
+		if ( name && !jQuery.cache[ id ] )
+			jQuery.cache[ id ] = {};
+		
+		// Prevent overriding the named cache with undefined values
+		if ( data != undefined )
+			jQuery.cache[ id ][ name ] = data;
+		
+		// Return the named cache data, or the ID for the element	
+		return name ? jQuery.cache[ id ][ name ] : id;
+	},
+	
+	removeData: function( elem, name ) {
+		var id = elem[ expando ];
+
+		// If we want to remove a specific section of the element's data
+		if ( name ) {
+			// Remove the section of cache data
+			delete jQuery.cache[ id ][ name ];
+
+			// If we've removed all the data, remove the element's cache
+			name = "";
+			for ( name in jQuery.cache[ id ] ) break;
+			if ( !name )
+				jQuery.removeData( elem );
+
+		// Otherwise, we want to remove all of the element's data
+		} else {
 			// Clean up the element expando
 			try {
 				delete elem[ expando ];
@@ -836,14 +890,16 @@ jQuery.extend({
 		// expando of getElementsByTagName
 
 		// Also, we need to make sure that the correct elements are being returned
-		// (IE returns comment nodes in a '*' query)
+		// (IE returns comment nodes in a '*' query)
 		if ( jQuery.browser.msie ) {
 			for ( var i = 0; second[i]; i++ )
-				if ( second[i].nodeType != 8 )
-					first.push(second[i]);
-		} else
+				if ( second[i].nodeType != 8 )
+					first.push(second[i]);
+		} else
+			for ( var i = 0; second[i]; i++ )
 				first.push(second[i]);
 
+		return first;
 	},
 
 	unique: function(first) {
@@ -851,8 +907,6 @@ jQuery.extend({
 
 		try {
 			for ( var i = 0, fl = first.length; i < fl; i++ ) {
-		try {
-			for ( var i = 0, fl = first.length; i < fl; i++ )
 				var id = jQuery.data(first[i]);
 				if ( !done[id] ) {
 					done[id] = true;
@@ -977,10 +1031,15 @@ jQuery.each( {
 
 jQuery.each( {
 	removeAttr: function( key ) {
-		jQuery.attr( this, key, "" );
+		jQuery.attr( this, key, "" );
+		this.removeAttribute( key );
 	},
+	addClass: function(c){
 		jQuery.className.add(this,c);
 	},
+	removeClass: function(c){
+		jQuery.className.remove(this,c);
+	},
 	toggleClass: function( c ){
 		jQuery.className[ jQuery.className.has(this,c) ? "remove" : "add" ](this, c);
 	},