misc fixes:

- don't attempt to resolve sourceUrl (breaks file urls)
- pass blob to loader
- add exact size progress update, if available
- google drive loader: switch to manual auth for any error

src/gdrive.js

@@ -88,7 +88,7 @@ class GDrive extends LitElement
   onLoad() {
     this.scriptLoaded = true;
     this.gauth('none', (response) => {
-      if (response.error === "immediate_failed") {
+      if (response.error) {
         if (this.state !== "implicitonly") {
           this.state = "trymanual";
         }