[chuck-users] Exp2

[Hans Aberg]

There seems to be no exp2 in 'chuck'. For time efficiency, I thought  
it might be better to use store intervals in natural base, using log  
and exp. But it turns out that C99 has both exp2 and log2 and the time  
difference (in C++) over using exp and log is insignificant; using  
pow(2, x) takes twice the time.

So I think chuck should have both exp2 and log2, and they should call  
the C99 functions.

   Hans