Fix for conversion to UTF8 process failing after the previous update

Hi cmorgan,

Here is a fix for the UTF8 conversion process. The problem was I switched to STRING_EQUAL_CASE because STING_COMPARE_CASE is marked as legacy, without inverting the expected result as required by WeiDU (I missed the warning in the documentation). This made the Windows test fail but it worked on my computer as git installs a Linux shell that was used when conv_tra.sh was called.

I also included English in the set of languages as there are characters in some dialogs (such as fiancée in lovetalks) that will crash the game.
I checked intallation in French and English and, thanks to an additional trace, I'm sure it uses the proper script now.

Please excuse me for the error in the previous version.