Exponentiation by integral exponents

[Tobias Schlüter]

FYI I have ported Andy's code for exponentiation by an integral exponent 
to our tree. This is an implementation of Knuth's algorithm which uses 
the minimum number of multiplications for exponents < 100. As an 
additional bonus there's no more need to special case an exponent of 
three, the optimal code is generated automatically. I'll submit this 
once my copyright assignment is handled.

Does anybody have any insight on how to write testcases for this?

- Tobi