Bug#882699: ngspice: Remove build dependency on elyxer to allow for the elyxer removal from Debian

[Gudjon I. Gudjonsson]

Hi

Now I have updated the git repository and only final testing is needed before upload.

But I get the following lintian warning.
W: ngspice-doc: privacy-breach-generic usr/share/doc/ngspice-doc/html/manual.html (http://elyxer.nongnu.org/lyx.css)

and I don't find any reference to elyxer when grepping the source.
Sven: Do you have any idea where this stems from?

Regards
Gudjon