Exponential operator

[Lars T. Kyllingstad]

In the 'proposed syntax change' thread, Don mentioned that an 
exponentiation operator is sorely missing from D. I couldn't agree more.

Daniel Keep has proposed the syntax

   a*^b

while my suggestion was

   a^^b

Neither of the natural candidates, a^b and a**b, are an option, as they 
are, respectively, already taken and ambiguous.

"Why do we need this?" you say. "Isn't pow(a,b) good enough?" And yes, 
pow(a,b) is just as good as mul(a,b) or div(a,b), but we don't use 
those, do we? Exponentiation is a very common mathematical operation 
that deserves its own symbol. Besides, bearophile has pointed out 
several optimisations that the compiler can/must perform on exponential 
expressions.

He also proposed that the overload be called opPower.

What do you think?

-Lars