Solving problem with the DeltaR calculation

This MR is to solve one problem with the DeltaR calculation in the jFEX forward jets, since the phi space between the different trigger towers are actually different from the the eta spacing. That should be taken into account, an therefore it changes the number of TT considered in the jet finding algorithm affecting also the trigger counts.

Additionally i have modified the way of how we read the SG jTower information. I simplified the reading in just one place (in the reset function, to actualise the actual pointer), to not read it several times in the algorithm, making it faster.