Implement file/blob/end.
When a file is received, download.
Add mimetype to link.
Add download notification, progress indicator.
Add docs to new GuacUI.Download object.
Clean up notification, add animated progress indicator.
Used fixed notation, rather than the classic Math.round() rounding idiom.
Add notification area. Preload images that would otherwise be loaded later, as such a load may fail due to resource starvation.
Better styling and alignment of notifications.
Add close button to notifications. Improve styling.
Use Blob.js and FileSaver.js for providing file downloads across platforms lacking blob and HTML5 download links.