Function: serlaplace
Section: polynomials
C-Name: laplace
Prototype: G
Help: serlaplace(x): replaces the power series sum of a_n*x^n/n! by sum of
 a_n*x^n. For the reverse operation, use serconvol(x,exp(X)).
Doc: $x$ must be a power series with non-negative
 exponents or a polynomial. If $x=\sum (a_k/k!)*X^k$ then the result is $\sum
 a_k*X^k$.
