#153

#153

#153

#138

#138

#138

#138

When uploading items with the same digest but different paths, the
status messages referred only to one of those filenames.

These changes fix that, considering each of those different files in the
status messages printed to stdout.

Also, upload_file() and upload_directory() now print paths consistently.

#155

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

#75

This allows tests to consider more complex directory structures.

(This is the tests/ directory mentioned in
#146).

These changes refactor the request queue, adding support for the
scenario where we want to download multiple copies of a file with the
same digest. (Previously only one instance of that file was created,
which resulted in files missing from the output.)

Addresses #146

Attempt to fetch directories in a given level using a single batch
request. If not possible to do so, fall back to using Read().