[#74] Fix PuiseuxXSeries evaluation at infinity
[#74] Fix PuiseuxXSeries evaluation at infinity

Correctly evaluate PuiseuxXSeries in the case when they are
centered at infinity by using "center" instead of "x0".

cswiercz/abelfunctions,abelfunctions/abelfunctions,abelfunctions/abelfunctions,cswiercz/abelfunctions,cswiercz/abelfunctions,abelfunctions/abelfunctions