Improve the external HRTF data file format
Improve the external HRTF data file format

Although more parameters are read from the file, some must currently conform to
specific values. In the future, these restrictions may be lifted.

franklixuefei/openal-soft,irungentoo/openal-soft-tox,cambridgehackers/klaatu-openal-soft,mmozeiko/OpenAL-Soft,AerialX/openal-soft-android,alexxvk/openal-soft,rryan/openal-soft,alexxvk/openal-soft,franklixuefei/openal-soft,arkana-fts/openal-soft,dapetcu21/openal-soft,cambridgehackers/klaatu-openal-soft,BeamNG/openal-soft,arkana-fts/openal-soft,mmozeiko/OpenAL-Soft,aaronmjacobs/openal-soft,cambridgehackers/klaatu-openal-soft,aaronmjacobs/openal-soft,EddieRingle/openal-soft,Wemersive/openal-soft,rryan/openal-soft,irungentoo/openal-soft-tox,jims/openal-soft,Wemersive/openal-soft,jims/openal-soft,BeamNG/openal-soft,EddieRingle/openal-soft