Suggestion to improve phobos std.string.icmp function

[James Pelcis]

The spec does say that they are unsigned.  There are probably other 
places, but one place is in 
http://www.digitalmars.com/d/interfaceToC.html under "Data Type 
Compatibility."

Chad J wrote:
> Yeah I was wondering about that.  I know the characters I was testing on 
> would all be negative if they were signed.  I worry though, if this 
> can't be relied on then they should all be casted to ubytes, just to 
> make sure.  Otherwise, if the spec says somewhere that chars are 
> unsigned (I couldn't find it), then it's probably best to leave it.