Fix pattern allocation in XM loader

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
[test] Add SoundFX loader test

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Handle memory allocation errors in SoundFX loader

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>