Change in list naming behavior when using overall and extra.col

[nabihlme]

In version 1.4.3, the Overall column was always presented to the extra.col function with the name "overall" (lower case). It did not matter whether the Overall column was named, placed on the left, set to TRUE, or otherwise not specified (default). In version 1.5.1, the Overall column is named exactly as specified in the function call.

Version 1.4.3:

table1(~ stuff | study, data=data, overall=c(left="Col"), extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "overall" "Study1" "Study2"
table1(~ stuff | study, data=data, overall="Col", extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "overall"
table1(~ stuff | study, data=data, overall=T, extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "overall"
table1(~ stuff | study, data=data, extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "overall"

Version 1.5.1:

table1(~ stuff | study, data=data, overall=c(left="Col"), extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Col" "Study1" "Study2"
table1(~ stuff | study, data=data, overall="Col", extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "Col"
table1(~ stuff | study, data=data, overall=T, extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "TRUE"
table1(~ stuff | study, data=data, extra.col=list(Pvalue=function(x,...){assign("x", x, envir=.GlobalEnv)})) ; names(x)
[1] "Study1" "Study2" "Overall" (Title case)

I had been relying on the previous behavior to set the overall column to NULL before calculating pvalues.
x$overall = NULL

The behavior is also used here:
#138 (comment)

[nabihlme]

This pull request also relies on the previous behavior:
#56