bugfix: do not allow null interval in hypervolume diff metric
Add moeoScalarObjectiveVector, a generic OV with templatized atomic type

Because sometime, we may want to use something else than a double (for example an eoDualFitness, a complex or whatever).
Use generic objective vector atomic type in HV continuator

One should not use specific OV types in continuators, but get it from ObjectiveVector::Type instead.
Add moeoDualRealObjectiveVector, to implement OV with feasability
Correct templatized types across ObjectiveVector-dependant code
Add missing arithmetic operators to eoDualFitness
Generic ObjectiveVector types
Merge branch 'fix/HVrange'
More generic eoDualFitness

Allow an imitialization on a double only, BUT an assert fails if it is not 0.0
Remove friendship on operators, because there is two differerent templated classes declared later.
More operators with base types.
Add constructors with explicit fitness assignement to IBEA
Add the DUAL fitness assignment class

Change a bit the machinery of moeoExpBinaryIndicatorBasedFitnessAssignment to allow subclassing.
Use the objective type instead of double in metrics