C++ EventPackets: abstract getting event index, precise what negative indexes really mean. Fix problem in back() when packet is empty, for vector this is undefined, we define it to be the same as front() in that case, the first element. This fixes out-of-range in iterators as a consequence.
C++ EventPackets: abstract getting event index, precise what negative indexes really mean.
Fix problem in back() when packet is empty, for vector this is undefined, we define it to be the same as front() in that case, the first element.
This fixes out-of-range in iterators as a consequence.

inilabs/libcaer,inilabs/libcaer,inilabs/libcaer,inilabs/libcaer