Add detector and station offset simulation

Consolidate detector and station offsets in the HiSPARCSimulation class.
Detector offsets for all station were checked for 4 days (2013/3/19,
2013/10/28, 2014/1/1 and 2014/1/2).
Offsets greater than 25 ns (abs) were ignored, to get rid of stations
with detectors at different altitudes (e.g. FOM)
When binned each showed a normal distribution with fitted sigmas around
2.77.