Revert "Fixed print_to_buffer() not ensuring output is UTF-8"

This reverts commit 39bcd977143d0df3f975dc38bcaf19688b96e0b3.
Commit was pretty much broken, translated all text including properly
encoded UTF-8 text with the assumption it was ISO-8859-1
Parses non-UTF-8 strings received with a backup encoding by default

Encoding is specified in ~/.config/squirrelchat/squirrelchat.conf,
however an option to change it in the settings has not been implemented
yet