Add ability to save images in folders based on their Patreon post

[Ruthalas]

Hello Xaeleph! Thank you for creating this tool.

I've added a few modifications to your script that helped it fit my use-case a little better and wanted to offer them as a pull request if you wanted to integrate them. If they aren't to your liking, feel free to decline and I'll just maintain my fork for my use.

I've added the following:

• When the "-folders" switch is used, the script generates a folder for each post to place images
• If the "-folders" switch is not passed, the script performs the same as before
• Folders are named with the date of the original post, as well as its original title (if those can be found)
• If the proper naming cannot be found, it uses the post number Yiff.party has assigned it
• Folder names are sanitized to prevent illegal folder names
• The error message for a non-200 response was modified to show what the failing response was

I tried to avoid tampering with the structure of your work, and to limit any modifications to the bare minimum required to make the folders work consistently.

I've tested it on several creators, with a variety of combinations of start/end pages and folders and so on, and it seems to work consistently and smoothly.

See the two attached images to get an idea what the output looks like:

[Xealeph]

Thank you very much, Ruthalas! I'm honestly very surprised you were even able to do anything with the unreadable hell of a mess I uploaded. Since I am also more on the lazy side in maintaining this project, I appreciate your work/contribution a whole lot. You also don't need to worry about changing the structure, since it would probably increase readability or optimize the code. :) (If you are not going to work on this again, then this is also completely fine, too! You already did more than I could ever hoped for. :+1:)