WIP: adding support for tidyfast

[xiaodaigh]

• [x] Wait for tidyfast to land on CRAN

• [x] Assess gdt https://github.com/mtfairbanks/gdt

• [ ] Add tests

• [ ] Pass check

• [ ] Merge with master

• [ ] submit to CRAN

• [ ] Integrate with new group-by framework

The below example already works!

library(tidyfast)
library(data.table)


disk.frame_to_split <- as.disk.frame(data.table(
  x = paste(letters, LETTERS, sep = ".")
))

disk.frame_to_split %>% 
  dt_separate(x, into = c("lower", "upper")) %>% 
  collect

delete(disk.frame_to_split)