added tlk_convert, a python dialog.tlk converter to utf8

currently used for conversion of chinese GBK tlk to a utf8 one to enable
the use of regular fonts

Signed-off-by: Jaka Kranjc <lynxlupodian@users.sourceforge.net>
added utf8-encoded tlk support
font: moved the zerospace detection from a config option to a fonts.2da column