Quick and dirty SED calculation

Taking care that we don't divide by integers, since that f%çked up the
results a bit.
Dose calculation now calculates more and properly

We make sure that integer division does not happen anymore.
Based on the calculated SED (from BAG formula) we calculate the number
of absorbed photons and try to estimate the photon flux.
Float/Int correction

We do no longer need to specify 100. if we import the future of
division.