dropbox oauth connection doesn't follow profile

The token handling for dropbox upload ignores profiles. The oauth token is saved in ~/.dropbox-api-config instead of inside the profile xml.

That causes 2 issues:

1) If you switch profile, you cannot connect the other profile to another dropbox account

2) Settings are scattered in my home. To delete all shutter settings it should be enough to delete ~/.shutter

As a sidenote: If one revokes the app permisson for shutter in the dropbox settings page, then shutter should restart the oauth setup on next upload. Instead it shows a permission denied that one cannot get rid of, until one finds out about ~/.dropbox-api-config and deletes it.