phobos commit, revision 2170


user: rsinfu

msg:
Fixed bug 5154: Class Range does not work in writeln.

* formatValue() deals with null, and delegates the actual work to private formatRange() added in this commit.
* Removed the isSomeString!T constraint of formatRange() because strings are already filtered out by formatValue().

http://www.dsource.org/projects/phobos/changeset/2170