Chessli v0.2.4

Closing #18 :)

Chessli v0.2.3

• Decouple 'last fetch time' between chessli games ankify and chessli openings ankify
• Clarify that games need to be analyzed on lichess in order to create
  mistakes flashcards
• Do not create csv files if they are empty
• Some more things

v0.2.2

• Fix bug that no new puzzles are ankified (fixes #12 )
• Slightly improve documentation and fix broken links

Chessli v0.2.1

• Documentation added
• Package uploaded to PyPi and so pip-installable
• Basic testing added
• Some feature extension
  • E.g. add csv-export
• Refactoring and bug fixes