bootES allows fractional `R` values and uses the floor

[dgerlanc]

This should throw an error for using a fractional R instead of silently taking the floor of 200.5.

set.seed(1)
dat = data.frame(scores=c(11, 12, 13, 14, 15, 16, 100, 379, 278))
bootES(data.frame(scores=dat), R=200.5, data.col=dat)