Enabled debug() to display non-Latin1 characters in Windows

I made another workaround for #233.

Unlike #233, ```debug()``` still uses ```stderr```. It converts a Unicode string into the Windows' local code page before outputting to ```stderr```.

Strictly saying, it cannot cover all Unicode strings. For example, if there is a string like this: ```日本語 & 한국어.mp3``` (it consists of Japanese, Korean and Latin-1 characters), it won't be displayed correctly in any environment.
However, perhaps it's enough for debugging for most users.