Make cipher checking case-insensitive

[Mark-H]

Working for a client, they experienced an issue where the cipher methods were all returned in lowercase while the requested $cipher is specified in uppercase. By uppercasing them all, FileLister works again, and threw in an extra log message for bonus points.

[ThijsFeryn]

Hi @Mark-H,

This is just a fork I used for a minor contribution last year. Please open up a PR on the upstream repository: https://github.com/splittingred/FileLister instead.

I'm going to remove the repo by the end of next week. Thanks for reminding me it was still out there ☺️

[Mark-H]

This PR builds upon your contribution, which has not been accepted upstream, which is why I sent it here instead.

[ThijsFeryn]

Thanks @Mark-H, I had no idea my PR wasn't accepted.

I don't really know how to test this code any more, but when I look at your commit, it looks pretty straightforward and the feature makes sense.

I appreciate your work. Guess I'll keep this repo around for a little bit longer then.