Use the same string replacement for keys in cache getter as setter

[BrewCurious]

This is a bit of a band-aid approach to deal with a specific use case for myself. What should eventually happen is a reevaluation of all is_file, write and read calls in base.php to have the filename strings always get passed through the fixslashes method before checking the filesystem to ensure consistent and filesystem-safe keys.

[BrewCurious]

@ikkez Is this something that could be merged? I'm having to manually update my core files anytime I sync with Composer to prevent this error. If there are any other considerations that I'm missing, I could help with the solutions. Thanks.

[ikkez]

thanks.. I'll keep this in mind to review all file path handling with fixslashes.. I'll merge this nevertheless for now ;)

[BrewCurious]

@ikkez Thanks for the merge. Could you let me know what the typical process/timeline looks like for updates made to master here getting updated via the link in the bcosca/fatfree-core repo? That's the package that I'm connecting to in my project's composer's config right now.