* AAC-Encoder

   - Introduce optional AACENC_SBR_RATIO encoder API parameter to configure
     dualrate or downsampled SBR explicitely. ELD makes use of downsampled SBR
     in default configuration.
     Modified file(s):
        documentation\aacEncoder.pdf
        libAACenc\include\aacenc_lib.h
        libAACenc\src\aacenc.h
        libAACenc\src\aacenc_lib.cpp

* SBR-Encoder

   - Implement downsampled SBR feature.
   - Revise sbr tuning parameter selection.
     Modified file(s):
        libSBRenc\include\sbr_encoder.h
        libSBRenc\src\bit_sbr.h
        libSBRenc\src\env_est.cpp
        libSBRenc\src\mh_det.cpp
        libSBRenc\src\nf_est.cpp
        libSBRenc\src\ps_main.cpp
        libSBRenc\src\sbr.h
        libSBRenc\src\sbr_def.h
        libSBRenc\src\sbr_encoder.cpp
        libSBRenc\src\sbr_rom.cpp
        libSBRenc\src\sbr_rom.h
        libSBRenc\src\sbrenc_freq_sca.cpp
        libSBRenc\src\sbrenc_freq_sca.h
        libSBRenc\src\ton_corr.cpp

Bug 9428126

Change-Id: I731720a10829272acaaf70b84525df00a09ff3d2