Fixed image links on `README.md`

Fixed a problem where bold colors were not activated

And now you can customize the GUI colors

Now you can also change the Fruit color

You can customize the Player colors on the configuration file!

Merged commit I forgot to push

`Utils::String::split()` does not trim anymore (closes #18)

Removed obsolete code on `Window`

Made Ncurses `WINDOW*` private, on the Window class

Removed some useless code

Commented on `Ncurses`

Commented on `Color`, `ColorPair` and `Colors`

Split `Utils::Base64` to its own file

Split `Utils::File` to its own file

Split `Utils::String` to its own file