New D coding convention style guide

[kris]

Walter Bright wrote:
> 
> http://thc.segfault.net/root/phun/unmaintain.html

Some good advice on tab-usage there:

"Never underestimate how much havoc you can create by indenting with 
tabs instead of spaces, especially when there is no corporate standard 
on how much indenting a tab represents. Embed tabs inside string 
literals, or use a tool to convert spaces to tabs that will do that for 
you."