Article on incremental compilation

[Zachary Yedidia]

Hi everyone,

I've been tinkering with setting up incremental compilation in my 
D projects by using `.di` files to ensure that a module is only 
recompiled if its interface changes (not its implementation). 
I've written an article about it here: 
https://zyedidia.github.io/blog/posts/4-incremental-d-knit/. 
Hopefully you find it interesting! Thanks!