pedigreeCross2() with use option accepting 'ebv', 'pheno', 'function'

[AudreyAAMartin]

So far pedigreeCross2() can produce a new population with selection based on 'gv'. This is because it can be set in the founderPop with SP$addtraitA and it will be spread through the population automatically when creating individuals. 'pheno', 'ebv' and 'function' has to be created for each generation to be able to rewrite the pedigree accordingly.