Function: qfbredsl2
Section: number_theoretical
C-Name: qfbredsl2
Prototype: GDG
Help: qfbredsl2(x,{data}): reduction of the binary quadratic form x, return
 [y,g] where y is reduced and g in Sl(2,Z) is such that g.x = y; data, if
 present, must be equal to [D, sqrtint(D)], where D > 0 is the discriminant
 of x.
Doc:
 reduction of the (real or imaginary) binary quadratic form $x$, return
 $[y,g]$ where $y$ is reduced and $g$ in $\text{SL}(2,\Z)$ is such that
  $g \cdot x = y$; \var{data}, if
 present, must be equal to $[D, \kbd{sqrtint}(D)]$, where $D > 0$ is the
 discriminant of $x$. In case $x$ is a \typ{QFR}, the distance component is
 unaffected.
