Fix archive.py and test_archive.py

archive.py:Archive.has_argument: Check setup.py also if argument is not found in setup.cfg
test_archive.py:TestArchive.test_find_list_argument_*: Change tests according to most recent accepted pull request
Cleaning of the code, some pep8 changes, see changelog
Update changelog, version number, setup.py
README.rst edited online with Bitbucket
Bitbucket doc page is offline, so I am trying.
Ok, no image for now.
Change shebang to python3
Add FileNotFoundError to try,except with subprocess.Popen
Update version to 1.1.0a, bugfix release
Replace nonexisting variable with the proper one in logging
Bump to 1.1.0b, bugfix