Digi speed up

Speed up the calo and scent digs by a factor of ~5 by factorising the time and energy loops.

This was tested on 100 single electron events and gave identical results. This is good in that it shows the new code is working but had since the results should have slight differences due to the baseline randomisation. Turns out that the default TRandom3() sets a specific seed so the random numbers always start from the same point (WTF) and you need to call TRandom3(0) to get a random seed. This has now also been updated.