CompileTime performance measurement

[Stefan Koch via Digitalmars-d]

Hi Guys.

I recently implemented __ctfeWriteln.
Based on that experience I have now implemented another pseudo 
function called __ctfeTicksMs.
That evaluates to a uint representing the number of milliseconds 
elapsed between the start of dmd and the time of semantic 
evaluation of this expression.

This does allow meaningful compiletime performance tests to be 
written.
spanning both CTFE and template-incitations timeings.

Please tell me what you think.