Pywaggle

Fixed: Forgot to export `plugin.upload_file` function.

Added `plugin.upload` and `plugin.upload_file` functions. These work like:

python
plugin.upload(bytes or file-like obj, labels={dict of metadata labels})


python
plugin.upload_file(filename or path, labels={dict of metadata labels})

Includes `pixel_format=rgb|bgr` support in data shim.

Bug Fix: More gracefully handle unexpected message types.

Updated internal plumbing to better support future return path.

Added standard debug logging support to pywaggle plugins. This can be enabled as:

python
import waggle.plugin as plugin
import logging

turn on debug logging
logging.basicConfig(level=logging.DEBUG)

plugin.init()
...