Add support implicit conversion between types

[Peter Alexander]

On Friday, 6 September 2013 at 11:32:11 UTC, Benjamin Thaut wrote:
> Its only a source of troubles in C++ because it is the default 
> behavior. But if you design a library it can make the usage of 
> your api easier and also you have a few more options to stay 
> backwards compatible with your old api.

It's not just that single arg constructors are by default 
implicit. Implicit conversions complicate things, like template 
argument deduction and overload resolution.