bugfix: clear previous pop when calling split
Correct types for fitness assignment in IBEA

While the default fitness assignment of IBEA is the Exp indicator one, the used interface is a binary indicator.
Makes operator() of Hypcontinues virtual when inheritating
reorder members, for safe initialization
Do not declare unused variable

This silents warnings about unused variables
Backport feasability when computing fitness in fitness assignment
In hyp continue, do not declare unused variable and group using
Allow scalar init of dual fitness; add a pop splitter

Scalar init of a dual fitness is dangerous, thus adds an explicit security against use of a partially initialized
object.
Use the pop splitter in the dual stat switch and in the MOEO dual fitness assignment.
Move the hyper volume dual difference metric in a separated file
Move the dual hypervolume continuator in a separated file
Insert a copyright header
Add dual hypervolume operators in the framewok header
Abstract base class for wrapping an estimator and a sampler as an eoTransform
Use EOType as a ref to the template in stats
Add a warning when computing stat in empty pop
Add a reference to the template type in eoStat
[COMPATIBILITY] Remove a unused parameter in eoInterquartileRangeStat constructor
Add an Nth element stat to compute median without sorting the pop
Missing header and include guards for moeoBinaryMetricStat
Merge branch 'master' of http://github.com/nojhan/paradiseo