Tibble support

[Maschette]

Hi,
I noted on your readme the use of as.data.frame() for tibbles for table1(). I was wondering if you had thought about building that into the function? I think I have what would be a working example below.

data<-dplyr::tibble(data.frame(x=1:3,y=4:6))

class(data)
#> [1] "tbl_df"     "tbl"        "data.frame"

if(tibble::is_tibble(data)){
  data<-as.data.frame(data)
}

class(data)
#> [1] "data.frame"

^{Created on 2020-01-31 by the reprex package (v0.3.0)}