Rename to `tsfeaturex`

[uribo]

Maybe because the old name (featuRe) is used, the demo code does not work.

library(tsfeaturex)
#> Loading required package: tidyverse

set.seed(516)

dat <- data.frame(expand.grid(day=c(1:7),id=c(1:100)))
dat$y <- rnorm(nrow(dat),5,1.5)
dat$y[1:3] <- NA

out.list <- extract_features(df=dat,group_var="id",value_var="y",features="all")
#> Error in packageVersion("featuRe"): package 'featuRe' not found

^{Created on 2019-03-06 by the reprex package (v0.2.1)}

I added a commit to fix this. extract_features() now works.