Massive refactor - PEP8

[vasekch]

Nothing changed on program logic, refactor only

• linting Python to PEP8 - addressing #15

  • indentation tabs -> spaces
  • spaces aroud +
  • space after ,
  • removed extra newlines
  • adding some newlines
  • ...

• removing unused module re

• moving declarations on top

• removing arbitrary ;

[vasekch]

I will create separate pull request for #13 and #14 after this one is merged as it changes almost every line, because of indentation

[cinek810]

I merged this together with pycodstyle check to TravisCI in #18 . Thank you very much for this valuable contribution!