Forward more Iterator methods for iter::Rev
Forward more Iterator methods for iter::Rev

`position` could not be implemented because calling `rposition`
on the inner iterator would require more trait bounds.

GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust