Improve name handling

[ticky]

This updates the name handling in two ways;

1. It updates the maximum length to 39 as discussed in Maximum name length seems to be one character too long #13; I've tested this repeatedly and it's consistently the true limit
2. Names are no longer transformed to uppercase, as GDMenu can handle mixed case titles just fine

Fixes #13

[sonik-br]

Thanks for the PR!
I can't test it right now as I don't have access to my dreamcast at the moment.
I do remember some users asking me to force the upercase but can't remember why. I think it was hard to read on a crt tv but might be wrong. Can you test it?

[ticky]

I don't have a CRT to test with, but it seems strange to me to restrict this for a subset of users when they could just use the caps lock key 😜

I'd suggest a compromise of making this a user-configurable setting, but I don't have enough experience with .NET core stuff to get far in that myself, I'm afraid

[sonik-br]

I will merge the PR later today.
Your changes are working perfectly. Also the texts are very readable in a CRT TV.
Was testing it now and found another bug. Renaming the game in the list is not working (at least in the windows build).