fix bug where importing vorbis comments to a flac file with no vorbis comment block corrupted the file

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

add wide (64-bit) versions of the FIR filter and inverse filter, remove unused arg from quantizing routine

use correct setlocale() setting, fix but where --list of vorbis comments was not going through utf8 conversion step