add check.names argument to data input

[zkamvar]

This is an update for the new adegenet version.

the alleles are named with x-y-z. When R reads them in, they are converted to x.y.z, which results in an error from adegenet because it uses a [LOCUS].[ALLELE] syntax, which is thrown off by extra periods.

Additionally, this should allow #146 to pass check.

[zkamvar]

I noticed that StartSNP.Rmd does not need check.names = TRUE since it converts the periods to underscores.