Commented out code

In a number of places there is commented out code present. It includes:

• - lib_rend.c, initMcBinauralRendering() (line 1963, under a comment /* Needs optimization, see issue 513 */)
• - lib_rend.c, rotateFrameSba() (line 4639, under a comment /unoptimized code for reference (full matrix multiplication)/
• - lib_rend.c, renderIsmToBinauralRoom() (line 4740, for loop)
• - lib_rend.c, renderInputMasa() (line 6591, under a comment /* ToDo */)
• - hrtf_file_reader.c, create_fastconv_HRTF_from_rawdata() (line 1831, if ( hHRTF == NULL ))

The commented out code should reviewed and removed if not needed anymore.