* automatically file type conversion support.
* check compiling in FreeBSD 4.8.
thanks to Marc Rene Arns <marc.rene.arnsAT@ATmichel-consulting.de>
for the report.
* fix bugs about file type conversion routine.
thanks to Narcis Suteu <nsuteuAT@ATtelemobil.ro> for the report.
* check file types which can be saved by Imlib2.