Moved the raw.help.title and help.title variables to the hhp-main template to make sure
a value is assigned after the namespace-stripping has been done. This prevents "Request
for title of element with no title" errors.
Added "//db:indexterm[1]|//ng:indexterm[1]" to the select expression of the global
htmlhelp.generate.index parameter, so that an index can be built for both DB 4 and
DB 5/NG documents (it's a little ugly, but a value needs to be assigned somehow).