Framework maintenance 1

Framework maintenance #1 (closed) consists of:

• correction/improvement of comments
• editorial changes
• simplification in Crend init: use 'set_f()' instead of 'for' loop
• address VE comment and rename 'is_masa_type_format' to 'is_masa_ivas_format'
• merge duplicated functions thr_f() and check_bounds()
• call PCA decoder only when needed
• replace IVAS_LFE_FADE_LEN_SEC_FLOAT by IVAS_LFE_FADE_NS; under SBA_CLEANING
• simplify SBA rendering conditions; under SIMPLIFY_SBA_RENDERING_LOGIC
• framework: introduce JBM reader. Get rid of printf() in init_enc(); when RF is specified at the encoder command-line and other than 13.2 kbps 32/48kHz is selected, the encoder does not stop but just prints out a message about "switching to normal mode" to replicate the EVS behavior
• cleaning: remove obsolete function IVAS_ENC_GetNumInputChannels() + add section comment
• cleaning: remove unnecessary includes and unused defines in bitstream handling related files
• maintenance: replace a magic number by the define NUM_BITS_FB_FRAMEGAIN_TBE