request for getSex for list of pedigrees and singletons

[thoree]

It would be nice with a version of getSex working
for a list of pedigrees and singletons:

library(pedtools)
v = list(singleton(1),singleton(2))
getSex(v,"1")
#> Error: Input is not a `ped` object

^{Created on 2018-12-05 by the reprex package (v0.2.1)}

[magnusdv]

This is implemented now, with getSex() allowing x to be a list of ped objects:

library(pedtools)
v = list(singleton(id = "a", sex = 2), singleton(id = 1, sex = 1))
getSex(v, c("a", 1))
#> [1] 2 1

^{Created on 2018-12-10 by the reprex package (v0.2.1)}