Remove with_ functions from devtools and use those from withr

[jimhester]

I am planning on submitting withr to CRAN in the next week or so. But I wanted to send a PR to iron out any bugs (and try the new Remotes: feature)

[jimhester]

This now works, all of the calls to with_ functions within devtools are replaced by calls to the corresponding withr functions.

However we need to decide how to handle calls to the old with_ function from other packages. There are three possibilities I see

1. Do nothing (this will break packages that use the functions, but will force them to update to withr functions immediately).
2. Continue to supply the functions and with a .Deprecated warning, remove them at a later date.
3. Export the existing functions as aliases to the corresponding withr functions.

1 isn't going to happen so 2 seems to be the best option, as part of the reason for splitting the functions out was so fewer packages would need to depend on devtools directly.

[hadley]

I think 1 would be ok if you did the revdep checks and informed the revdep maintainers

[jimhester]

Oh well... already did the deprecation work!

bee53b7 should be good (assuming it passes).

[hadley]

Thanks!