[PATCH 1/3] Automatic evaluation of (e^t)^s = e^(ts).

[PATCH 1/3] Automatic evaluation of (e^t)^s = e^(ts).

If it safe to evaluate (e^t)^s = e^(ts) at least in two cases:

a) t and s are reals, the respective formula can be found in
any analysis textbook.

b) if s is an integer, then the ambiguity of t up to the term 2*Pi*k
does not cause a different value.

Signed-off-by: Vladimir V. Kisil <kisilv@maths.leeds.ac.uk>