patch for expansion of log.

Hello, I found out that trying to calculate log(a*x+b*x*x*log(x)).series(x==0,3) does not terminate. This is because in the function the argument has a pole even if a log(a*x) is subtracted. The attached patch should solve this. With this patch the result of the calculation is (log(x*a))+(a^(-1)*b*log(x))*x+(-1/2*a^(-2)*b^2*log(x)^2)*x^2+Order(x^3) as expected. Have a nice weekend, Chris Dams