Add example project, fix bugs in README

[danielcompton]

This is a little bit rough, but I wanted to put where I'd got to to help others.

Relates to #11.

[franzwilhelm]

please merge

[Mark-Hetherington]

I've gotten this working within a larger python3 app engine application generating the signed URL. It's a bit of work to pare it back to a minimal example. The crux of it is a call to a url that checks the users authentication and authorises a signed URL for a particular file path.
That is basically a matter of calling blob.create_resumable_upload_session(), and the result gets given to the browser allowing gcs-browser-upload to do the upload.
If I find some time and I can figure out how to update this pull request I'll try to add a quick example.

[oliverwoodings]

Thanks for this, sorry it took 2 years to merge, my notifications weren't enabled for this repo 🤦‍♂