ConsolePortKeyboard: backspace erases half of multi-byte character

[ghost]

When backspacing russian characters I have noticed that first it becomes a question mark, then it gets deleted, which means that top byte gets erased first, then lower. Can you please add some option(or detect it somehow) for non-ASCII languages to have multibyte characters properly deleted?

[seblindfors]

There are actually equivalent cursor functions for multibyte characters, but I never used them since it wasn't relevant to English. I'll look into it and if it's a minor fix it'll be added in the next patch.