[NTG-context] staticMPfigures can overrun output streams

[Sanjoy Mahajan]

In another thread, Hans mentioned the 2006.09.25 beta.  I tested it
against this test file and it works great:

\starttext
\dorecurse{20}{\startreusableMPgraphic{\recurselevel}
  draw fullcircle scaled 3mm;
\stopreusableMPgraphic
\placefigure[here,none]{}{\reuseMPgraphic{\recurselevel}}}
\stoptext

I just added this test to the contexttest svn repo.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
         --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.