Help specification

[Christopher James Lahey]

Shaun and I talked for a while today about the help spec, in particular
the help: URI -> file mapping, and I wanted to share the stuff we talked
about.

We decided that the right way to do this is to have #blockid to specify
references inside a particular docbook file.  This will work for both
help: and file: URIs.

Also, when a directory is specified, if index.html doesn't exist,
index.docbook will be checked for.  If it exists, we'll use it.

This allows for very simple URIs:

help:gnome-terminal#usage

This would show the generated html that includes the usage block of the
file: /usr/share/help/en/gnome-terminal/index.docbook

You can also make more complicated URIs if you want to specify specific
bits.

I've updated the wiki and will be implementing this in yelp.

The wiki used to have the old KDE system which looked to see if the file
name listed could be generated by index.docbook, but this means that you
can't reference blocks in arbitrary docbook files, only ones in
index.docbook files.

Thanks,
   Chris