0.4.1

This is a minor release. Apart from bug fixes, it adds the 'docker upload' command to substitute input files in docker containers, and a set of signals that will be used by future plugins.

Bugfixes:

• reprounzip showed duplicated logging messages
• Makes 'run' commands not fail if the command returns an error code
• Unicode issues with Vagrant on Windows Python 3
• Warning for files read then written didn't show the filenames
• Fixes resetted input files breaking 'showfiles'

Features:

• 'docker upload' command
• Adds signals (currently unused, needed for future plugins)