loader: support require api

[yiminghe]

// http://x.com/y/z.js
// generate KISSY.add by tools
KISSY.add(function(S, require, exports, module){

// code start ---------------
var dom = require('dom'); // static load

var x = require.toUrl('./x.css') // http://x.com/y/x.css

x = require(['c'],function(c){
// dynamic loading
});
// or
x = require.async(['c'],function(c){
// dynamic loading
});

// export functionality
exports.init = function(){
};
// code end -----------------

});

[minghe]

已经这么用了，比以前的写法更自然方便

[yuanyan]

Really really cool.