wip (on custom-covar branch)

v6.0. Added mean visits per patient (without FeatureExtraction)

bumbed version to v1.3

added version.txt to export. bumped version to 4.1

all default covars! does not include continuous

added tidyverse back in, can remove later.

default table1

counts only

Merge branch 'master' of github.com:Sigfried/HivDescriptive