help: cleanup, indentation, remove 'used by'
rename help, functions, and variables to mmhelp, mmfunctions, and mmvariables
add missing checks for mmfunctions and mmvariables
mmfunctions: no need to specify input file stream index in ffprobe
add handling for files with at least two mono tracks

The first mono is mapped to left and second mono to right of the stereo
output.
fix_volume: cleanup and move much of it to get_volume_adjustment function
update & cleanup getopts process
add cropdetection handling for make broadcast