improve error checking and efficiency of octave audio callback function * audiodevinfo.cc (octave_play_callback): Check for non-null player object. Move computations of constant values outside of loop. Invert nesting of switch statements and loops. Use const pointer to data instead of RowVector::elem method. (portaudio_play_callback): Check for non-null player object.

*~
*.user
*.o
*.a
Makefile*
*.pdb
debug/
release/