Some Audiosculpture songs loaded by Furnace and libopenmpt

[aargirakis]

Need to add check for Audiosculpture format in Furnace and libopenmpt. Libopenmpt seems to play the files correctly but as I remember it doesn't support loading of external samples yet.
Audio Sculpture.zip

[ciros88]

confirmed. we should use libxmp or uade for audio sculpture (dunno which is better in this case). but here an external format detection library should be used

[aargirakis]

I don't know how to differenticate Startrekker and Audiosculpture, both have magic bytes "FLT4". Startrekker plays fine in libopenmpt, but Audiosculpture not.

[Kaens]

NostalgicPlayer plays the .adsc files, why not borrow from that? BTW the magic can be "EXO4" too.