CPE encoder subfunctions conversion and integration [allow regression]
[x] stereo init funcs, set_transient_stereo, set_stereo_mode, signal_clas, pitch_ol functions, clean up of pre_proc_ivas and front_vad
[x] Modified acelp_fast_fx
[x] Integrated smc_gmm in pre_proc_front_ivas_fx
Edited by Sandesh Venkatesh