Various contributions

[micho]

Thanks for the code! We're going to use it at Teambox.

I'm sending some fixes we had to make:

• For REST compatibility I added support for 201 responses on upload
• I made Chrome add nice filenames

[Rovak]

Hi Micho, thanks a lot for the contributions! Really nice improvements (and fixes) in the overall code, i'll merge it and bump the version number.