change mixins

[Walter Bright]

Bill Baxter wrote:
> I have had one use for templates that are both stand-alone and mixed
> in -- that's collections of aliases and utility functions based on a
> particular type.


You'll possibly run into a serious problem doing that. With templates, 
the name lookup is done in the scope of the template definition. With 
mixin templates, name lookup is done in the scope of the template 
instantiation.