Function: isfundamental
Section: number_theoretical
C-Name: gisfundamental
Prototype: G
Help: isfundamental(x): true(1) if x is a fundamental discriminant
 (including 1), false(0) if not.
Description:
 (int):bool       Z_isfundamental($1)
 (gen):gen        gisfundamental($1)
Doc: true (1) if $x$ is equal to 1 or to the discriminant of a quadratic
 field, false (0) otherwise.
 The function accepts vector/matrices arguments, and is then applied
 componentwise.
