Feature request: contfrac of unnormalized fraction

[Dirk Laurie <dirk.laurie@gmail.com>]

If p and q are large integers or polynomials of very high degree
then contfrac(p/q,,nmax) with small nmax is unnecessarily slow
since a complete gcd of p and q, equivalent to taking contfrac
much beyond nmax, is done when p/q is formed.

contfrac([p,q],,nmax) would be useful to avoid this.