std.range.byLine

["Nordlöw" via Digitalmars-d-learn]

I'm missing a range variant of byLine that can operate on strings 
instead of just File.

This is such a common feature so I believe it should have its 
place in std.range.

My suggestion is to define this using

splitter!(std.uni.isNewline)

but I'm missing std.uni.isNewline.

I'm guessing the problem here is that newline separators can be 1 
or 2 bytes long. that is it Separator must be of the same time as 
Range.

Should I add an overload in PR?

Destroy.