Support of UTF-8

[Joe91]

This is just a proposal.
With these changes the FTP-Server adds support for UTF-8 and for white-spaces in filenames and folders.
Also Filezille now detects the UTF-8 mode if set to "automatic-detection".

Since UTF-8 is fully supported by Arduino 2 filesystems there should be no problem to enable this.
But it would also be possible to only enable UTF-8 support if you configure it when adding the filesystem.

Thanks a lot for this great FTP-Server! It really works great for me :-) ...

[peterus]

@Joe91 thank you very much for your contribution! I will fix the style check etc. than I will merge your changes 😉

[Joe91]

Oh, sorry for the style-error.
So do you want the support for spaces and utf-8? I was not sure wether it was inteded the way it was...
If you like we can also put this changed behaviour on an option (for example in the register-function of the filesystem).

[peterus]

I like your changes! Don't worry ;) I will fix the last issue and than merge everything :) thanks for your support!

[peterus]

closing #41