Detailed description 

The behavior below is neither the expected one (as documented) nor the desired one:
> integral(exp(x),[infty;0]);
[@NaN@;@Inf@]
> dirtyintegral(exp(x),[infty;0]);
0
>
As a matter of course, the integral makes perfect mathematical sense but Sollya should refuse to compute it, giving some kind of a warning.

