add support for 64bit datapath through FIR filter, update logic for automatically choosing the qlp coeff precision
add support for 64bit datapath through FIR filter, update logic for automatically choosing the qlp coeff precision

waitman/flac,waitman/flac,LordJZ/libflac,fredericgermain/flac,kode54/flac,fredericgermain/flac,Distrotech/flac,LordJZ/libflac,Distrotech/flac,waitman/flac,Distrotech/flac,waitman/flac,Distrotech/flac,fredericgermain/flac,kode54/flac,LordJZ/libflac,kode54/flac,LordJZ/libflac,waitman/flac,kode54/flac,fredericgermain/flac