Attempt to fix Issue 263

[yasirs]

sapply returns a matrix when it should return a list

https://github.com/Rapporter/pander/issues/263

[yasirs]

I seem to be having a problem using my supposed fix because of the way R assigns to data frames. Consider:

> a <- data.frame(a=c(1,2), b=c(2,3), c=c("a,b","c,d"), stringsAsFactors = F)
> a$c <- strsplit(a$c, ",")

Now, a simple re-assignment fails:

> a[,3] <- a[,3]
Warning message:
In `[<-.data.frame`(`*tmp*`, , 3, value = list(c("a", "b"), c("c",  :
  provided 2 variables to replace 1 variables

[codecov-io]

Current coverage is 79.40% (diff: 52.94%)

Merging #264 into master will decrease coverage by 0.13%

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