Make the doc string for isValidMode more clear
Make the doc string for isValidMode more clear

also make sure the symbol is exported with EXPORT_CALL

liblouis/liblouis,liblouis/liblouis,BueVest/liblouis,BueVest/liblouis,BueVest/liblouis,hammera/liblouis,hammera/liblouis,hammera/liblouis,hammera/liblouis,BueVest/liblouis,BueVest/liblouis,hammera/liblouis,hammera/liblouis,liblouis/liblouis,BueVest/liblouis,liblouis/liblouis,liblouis/liblouis,liblouis/liblouis