Error Handling and Logging

[dtext]

After Milestone 0.2, we should rethink error handling and logging inside the storage providers. They also need to be resilient in the face of failure. For example, errors we don't anticipate are:

• no internet connection
• unsupported media type for hoster
• upload failed for some other reason
• API change
• ...

If I call an upload(file) method, I expect an error to be raised when that method does not complete successfully. That error could then be handled by me, the individual storage providers don't need to be concerned about how to inform the user about errors.

There was a change a while back where the storage provider's functionality was moved up to the module level for the sake of simplicity. Now I think it could be better to think about storage providers as classes with state again. I believe that would make them more maintainable.

p.s.: This is labeled as a bug because the any of the listed errors has the potential to crash the storage provider modules.