Add safety checks before starting a full regression.

[andreabonvini]

Check if, given a list of events times and a series of parameters (windowLength, delta, etc...), it is possible to carry out a fullRegression without experiencing any crash. (e.g. see

pointprocess/src/pointprocess/PointProcessDataset.cpp

Line 37 in c6d83f3

assert (events_times.size() >= AR_ORDER_ + 2);

)