interface/FBaseSimEvent.icc

I removed the definition of static FSimTrack, FSimVertex and FSimVertexType.
These statics used to be returned by functions track(int i), vertex(int i), vertexType(int i) in case the index i was out of range.
Now instead an error is thrown.
To avoid indices out of range, the following changes were made:

interface/FSimTrack.icc

The function FSimTrack::noEndVertex() now first of all checks if FSimTrack has an end vertex
(index of end vertex >= 0)
associated and returns false if this is not the case.

src/FSimEvent.cc

The function FSimEvent::load(edm::SimTrackContainer & c, edm::SimTrackContainer & m)
now verifies wether a track has a mother (index mother >= 0)
before evaluating the properties of the mother.