update CWG2R based on suggestions by @mmlopezu
update CWG2R based on suggestions by @mmlopezu

sessionInfo:
R version 3.2.3 (2015-12-10)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11.3 (El Capitan)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] git2r_0.13.1

loaded via a namespace (and not attached):
[1] htmltools_0.3   tools_3.2.3     yaml_2.1.13     memoise_1.0.0   rmarkdown_0.9.2
[6] knitr_1.12.3    digest_0.6.9    devtools_1.10.0
NESCent/popgenInfo,bjcochrane/popgenInfo