Function: ellidentify
Section: elliptic_curves
C-Name: ellidentify
Prototype: G
Help: ellidentify(E): look up the elliptic curve E in the elldata database and
 return [[N, M, ...], C] where N is the name of the curve in J. E. Cremona
 database, M the minimal model and C the coordinates change (see
 ellchangecurve). 

