[BUGFIX] Fix "File name too long" errors

[thegass]

• some artists use ZeroWidthSpace in their names/releases (Why? WTF) which results in file/directory names longer than 255
• solution remove ZeroWidthSpace from artist & releasenames

fixes #56 for my usecase.
all my problematic releases are downloading for now.

[Ezwen]

That's surprising indeed that this happens… I think some languages use these characters to specify when can a word break can occur. But since a file name should always be on a single line, you are completely right that they should be removed.

To simplify your proposal, I suggest we switch the type of the existing map UNICODE_CHARS_REPLACEMENTS from <Char, Char> to <String, String>, which would allow you to add this new case without creating a new map and a new conditional. Would you be OK to make this small change?

[thegass]

sounds good to me.

[Ezwen]

Let me know when you have time to make the change and I'll do a second review.

Sorry about the conflicts that appeared, I merged another PR that changed the same code area :)

[thegass]

rebased my pr and unified the maps.
hope it's ok.
this is the first kotlin project I'm working on.