With this pull request I'm trying to support sqlite database urls inside the utility function dburl2dict.

As you can see from the patch, I decided to initialize user, pw, host and port to empty strings, then to pop corresponding items from the output dictionary before returning it.

Another solution would have been to initialize out with the sole mandatory fields (i.e. dbn and db) and fill optional ones if set, but in this case all the existing doctests should have been rewritten as well (the keys insertion ordering in the output dictionary would have been different).