Multiple improvements

[HaDeSMonsta]

• I reformatted the logger to give consistent logging and added levels for successful downloads and failures.
  • Those changes include a new format and new colours, green for successes and blue for debug/info
• Failed downloads now get automatically deleted
• Download progress can be monitored live because successes and failures are written in a separate file
• The started download threads are now returned and joined after all of them were started, when they are all done the successes and failures will be written again, but sorted
• Added a shell script to rerun the program until there are no failures (this will work because failed downloads will no longer be kept)

[wolfswolke]

Thank you for the PR. I tested it on Windows and everything works from what i can see.