Translation: PL - Polish

[MiloszFilimowski]

To make it easier for anyone to contribute I created a fork: https://github.com/MiloszFilimowski/remember-pl

Here is a list of changes to be made:

• Prepare for translation (create a new file and a fork)
• Translate Chapter 0 - In progress (@MiloszFilimowski)
• Translate Chapter 1
• Translate Chapter 2
• Translate Chapter 3
• Translate Credits
• Translate Flash cards (remaning ones, not translated)
• Translate interface labels etc
• Add a hint of silliness at the end of the title, like "ish" or "sorta" to the current working title.

Please feel free to translate any part that's not In progress and submit a PR to my repo. If a given section is too large we can always make it smaller :D

After everything is translated we'll merge it into the main repo.