[dev-context] \setuppapersize: mirrored, negative, rotated, etc. not working in mkiv

[Sietse Brouwer]

Hi,

While working on the wiki I discovered that mkiv fails on a few
\setuppapersizes keys. Minimal example below. I'm using
mkiv, 2012.04.19 23:18. mkii does it all with no problems. I
discovered this while working out what the various keys do; I myself
don't need a fix.

--Sietse

% negative causes an 'undefined control sequence' error.
% So do mirrored, 90, 180, and 270.
% rotated causes no error, but does nothing

% \setuppapersize[A6][A5] % works

\setuppapersize[A6,negative][A5] %fails

\starttext
asdf
\stoptext