SVG terminal driver

[Ethan M. <merritt@u.washington.edu>]

I had to re-work the logic for handling special characters
in SVG_put_text in order to make it work again on my machines.
It was suffering from bug #1575007 and also from a 3 Oct 2006
patch that changed the non-enhanced text code path.

I put the revised version in cvs, but not yet in the
4.2-rc branch.

With the revised logic, I am able to build the entire
all.dem test set as SVG web pages and have not noticed any
errors in the character string handling for 'normal'
character encodings.

On the other hand, the additional special-char tests in the
3 Oct patch were not necessary for my two test svg-viewers.
So I conclude that they were intended to fix a problem with
a different set of viewers.  Please re-test the current
version to make sure I haven't broken it for you at the same
time I was fixing it for me.

Assuming it works for you also, should we copy the cvs
version over to the 4.2 branch for inclusion in -rc2?

[ This is a bigger change than most of the -rc1 bug fixes,
 but I don't think the version of svg.trm that went into
 -rc1 was heavily tested anyhow, so it's not like we have 
 diverged from something known to be solid. ]

-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle WA