Usage: A = permuteQS(A, P [,'conj'])
permute input QSpace using given permutation P.
Optional trailing 'conj' also applies (complex) conjugation
(note that this also affects real QSpaces in that qdir and
itags are altered!).
For convenience, P [,'conj'] may also be represented as
single string, e.g. [2 1],'conj' is equivalent to '2,1;*'
or '21*' where the convention on string notation
follows that of contraction indices [ctrIdx].
NB! [06/02/2019] the provided permutation can be shorter
than the rank of the QSpace; in this case it only affects the
leading range of indices, i.e., acts like an identity
on the remainder of indices.
AW (C) Aug 2006 ; May 2010 ; Oct 2014