用于Html5预加载图片资源插件，具备加载进度功能
* @description loadImages can preload images and after each image load completed can callback process
* @param {object} options - past setting parameters
* @param {string[]} options.data - images url array
* @callback options.step - each step callback function
* @param {number} - process number
* @callback options.complete - all images are loaded
* @param {boolean} needOneStep - increase by 1 each time
* @param {string} path - images data string common path
* @return {boolean}
* @example
* loadImages({
* data:["1.png", "2.png", "3.png"],
* step:function(num){},
* compelte: function(){},
* needOneStep: true,
* path:"/images"
* });