#105 Add "see also" to guidelines pages based on index

[Elli Mylonas]

As part of the navigation overhaul, we want to add "see also" links at the bottom of the transcription and other pages. These will the be same as the index entries - Whatever elements are used to tag the Epidoc feature on that page
Example: on http://www.stoa.org/epidoc/gl/latest/trans-struckovererasure.html , <subst> and <add> are the elements used to encode over-struck erasures. So at the bottom of the page, other epidoc features that also use <subst> and <add> will be listed as "See Also" at the bottom of the page.
In this case, those will be
for the <add> element: Text Addition by Ancient Hand, Addition With Mark, Ancient Corrections (Where Both Old and New Text Can Be Read), Ancient Corrections (Old Text Lost), Text Struck Over Erasure

for the <subst> element: Ancient Corrections (Where Both Old and New Text Can Be Read), Text Struck Over Erasure

[BODARD Gabriel]

Sample index created as per [r2420] and uploaded to dev (see e.g. http://www.stoa.org/epidoc/gl/dev/trans-possiblevacat.html ). If this seems okay to everyone, I'll add divGen[@type=seealso] to other pages in the GLs, and this will become global. (Or we could even trigger it automatically.)

[BODARD Gabriel]

Added the "seealso" divGen globally, and pushed result to dev. Any tweaks to this can be made in future versions, but I'm declaring this done.