Simple HTML5 uploader
##Usage
new Uploader({
target: "#upload", // jQuery search string (required)
url: '/upload', // url to upload (required)
event: 'click', // jQuery event to target for start upload (not required, by default 'click')
params: { id: 1 }, // POST params to send (not required)
multiple: true, // multiple file choose (not required, by default 'false')
load: function(response){}, // function to call after load (not required)
progress: function(response){}, // function to call on load progress (not required)
});