Let src/usr.bin build with recursive parallel make..
- add .WAIT and .NOTPARALLEL in a few places
- change ${MAKE} print-objdir to ${PRINTOBJDIR}
- convert other ad-hoc forms to use ${PRINTOBJDIR}

add audiorecord and audioplay tools. audioplay does .au and .wav files. audiorecord makes .au files only. uses parts of audioctl..