Data uri failure fix
Created by: josedcs
The bloburl does not have the same limitations as a data uri so download does not fail in Chrome. Since bloburl is now inserted into dom, downloading on firefox works now as well.
Changed flow of downloading documents by adding a button and an extra click. One must first "fetch" the document before "downloading" the document.
A button indicates that the document must be fetched and the button changes to download after the document is fetched and bloburl is generated.
Added styling to slot buttons so that they are the same size as line.