Function: plothrawexport
Section: graphic
C-Name: plothrawexport
Prototype: GGGD0,L,
Help: plothrawexport(fmt, X,Y,{flag=0}): plot in high resolution
 points whose x (resp. y) coordinates are in X (resp. Y), returning
 the resulting picture as a character string. If flag is 1, join points,
 other non-0 flags should be combinations of bits 8,16,32,64,128,256 meaning
 the same as for ploth().
Doc: given $X$ and $Y$ two vectors of equal length, plots (in high precision)
 the points whose $(x,y)$-coordinates are given in $X$ and $Y$, returning the
 resulting picture as a character string which can then be written to a file.
 The format \kbd{fmt} is either \kbd{"ps"} (PostScript output) or \kbd{"svg"}
 (Scalable Vector Graphics).

 Automatic positioning and scaling is done, but with the same scaling factor
 on $x$ and $y$. If $\fl$ is 1, join points, other non-0 flags toggle display
 options and should be combinations of bits $2^k$, $k \geq 3$ as in
 \kbd{ploth}.
