MAY2011_NEURALTRANSDUCTION - calculates the auditory nerve response

Input parameters:

`bm`	matrix containing signals after auditory filtering
`fs`	sampling frequency [Hz]
`haircellMethod`	can be 'none', 'halfwave, 'roman', or 'envelope'

audNerve

matrix containing the signals after inner hair cell processing

may2011_neuraltransduction simulates the neural transduction in the inner ear by means of lowpass filtering of the signal envelope