Function: rnflllgram
Section: number_fields
C-Name: rnflllgram
Prototype: GGGp
Help: rnflllgram(nf,pol,order): given a pol with coefficients in nf and an
 order as output by rnfpseudobasis or similar, gives [[neworder],U], where
 neworder is a reduced order and U is the unimodular transformation matrix.
Doc: given a polynomial
 \var{pol} with coefficients in \var{nf} defining a relative extension $L$ and
 a suborder \var{order} of $L$ (of maximal rank), as output by
 \kbd{rnfpseudobasis}$(\var{nf},\var{pol})$ or similar, gives
 $[[\var{neworder}],U]$, where \var{neworder} is a reduced order and $U$ is
 the unimodular transformation matrix.
