Merge pull request #13 from esben/master

Features for milestone 0.1 and full unittest coverage
Update README.md with Codacy badge
Fix use of mutable values as default function parameter value

Signed-off-by: Esben Haabendal <esben@haabendal.dk>
Whitespace cleanup according to PEP 8

Signed-off-by: Esben Haabendal <esben@haabendal.dk>
more PEP 8 whitespace cleanup *FIXUP*

Signed-off-by: Esben Haabendal <esben@haabendal.dk>