v0.6.2

Changed

• Made the timestamp_column_name required by all calculators and estimators optional. The main consequences of this
  are plots have a chunk-index based x-axis now when no timestamp column name was given. You can also not chunk by
  period when the timestamp column name is not specified.

Fixed

• Added missing s3fs dependency
• Fixed outdated plotting kind constants in the runner (used by CLI)
• Fixed some missing images and incorrect version numbers in the README, thanks @NeoKish!

Added

• Added a lot of additional tests, mainly concerning plotting and the Runner class