signal_energy_nodc does not consider remainder samples after loop

signal_energy_nodc loops over samples to calculate RMS^2. This is the loop used in the function:

for (i=0; i<(length>>2); i++) {

The function only considers ((length >> 2) << 2) samples. This makes no difference when amount of samples is a multiple of 4, but we also call the function on length 6, which means 2 / 6 samples are not added to the result.