Optimization of the CBR loop

celt/vq.c

silk/enc_API.c

silk/fixed/encode_frame_FIX.c

silk/fixed/process_gains_FIX.c

silk/float/encode_frame_FLP.c

silk/float/process_gains_FLP.c

silk/gain_quant.c

silk/main.h

src/opus_encoder.c