[Pre-RFC] Change the Range struct to support inclusive ranges

[oli-obk]

@stebalien

My specific use case is that I would like to replace the rand crate's custom Range with a standard Range.

I'll save you the trouble: Range syntax distribution by oli-obk · Pull Request #9 · rust-random/rand · GitHub

I fully agree that something needs to be done about the ranges though. The other thread kind of died.