Infrastructure updates to the QT4CG spec repository

Hi folks,

PR #143 says:

  This PR doesn't make any technical changes (and it probably won't
  build correctly as a PR, so I'm just going to merge it).

  1. I tinkered a little bit with the URIs on the specifications so that
  they point to more accurate URIs.

  2. I've tried to make a few of the XSLT files "less chatty". I'd like
  to make it easier to see what the errors and warnings are so that we
  can resolve them. It's the sort of thing that bugs me, so if no one
  else does it, I'll probably chip away at them as we go.

  3. I reworked the way that the XPath Functions and XSLT specifications
  are built. I've pulled the tasks out of the ant files and implemented
  them directly in Gradle. (The XPath and XQuery specifications are as
  yet unchanged, they're more complicated and this already took longer
  than I had anticipated.)

  4. The specification/{specid}/build and specification/{specid}/html
  directories are no longer used. All of the build and intermediate
  files are under build. (For XPath Functions and XSLT.)

  5. I stopped trying to build all the namespace documents. Those aren't
  useful unless they're installed in the "real" URIs and I have no idea
  if/how we'll be able to update those. When we're closer to the end, I
  can get the namespace documents building again. For now, it's just
  faster not to.

It's now easier to see what is happening and Gradle will do a better job
of managing the dependencies. So if you are building it locally, it
should do less work on each build.

Everything should just build the same way it used to. Changes to the
sources or the stylesheets should cause the right builds to run. It is,
of course, possible that I've broken something. I tried to check
everything, but there are a lot of moving pieces here. Comments,
questions, and complaints most welcome.

I’m going to merge that next. If I’ve broken something, please tell me.
And accept my apologies in advance!

                                        Be seeing you,
                                          norm

--
Norm Tovey-Walsh
Saxonica