Adds support for older AMF 1.0 modules. This was broken at some point in the past because someone (correctly) realized that not all AMF 1.0 modules have truncated loop start/end values. I had to track down DMP 2.32 to make one of these myself, since the modules libxmp cites have vanished. reborning.amf.zip
Note 0x7f doesn't duplicate the previous event (like AMF.TXT claims), but instead tells DSMI to retrigger the current playing note in some obscure situations. The best thing to do is to ignore these and (someday) to add support for the Protracker 2.3 instrument change quirk this was trying to emulate.
This patch fixes a couple of AMF issues that weren't addressed by #36. These were found here: https://github.com/libxmp/libxmp/issues/350.