Can i plz has some template instantiation error stack traces?

[Christian Kamm]

>> LDC can haz.
>>
> 
> orly?
> 
> As in haz them now? or can potentially haz at some point in the future
> if someone decides to do it?

Can haz now. Currently looking like so

templerror.d(9): Error: identifier 'wrong' is not defined
templerror.d(12): Error: template instance templerror.bar!(int[][][]) error
instantiating
    instantiatied in templerror.d(12): bar!(int[][])
    instantiatied in templerror.d(3): bar!(int[])
    instantiatied in templerror.d(16): foo!(int)

and triggered by errors and static asserts.

We had a brief slide about them in our Tango Conference talk. I hope it'll
be up eventually... :)