Tweak sysutils/serpentine version 0.7_9
Update finance/R-cran-urca to version 1.2.8_2
Update math/R-cran-labeling to version 0.2_2
Update math/R-cran-fracdiff to version 1.4.2_3
Update converters/R-cran-rjson to version 0.2.13_2
Update devel/R-cran-gsubfn to version 0.6.5_4