Kill implicit joining of adjacent strings

[klickverbot]

+1 on this.

While implicit joining can certainly be useful in C in some cases, D has 
the ~ operator for such cases.

Since compile-time primitives are guaranteed to be folded anyway (IIRC), 
I can imagine no situation where the benefits of banning implicit 
joining (reducing the chance for bugs, less special cases) would not 
outweigh the costs of an additional character to type.