As discussed in #3, the sound library doclet reference requires some post-processing steps to generate documentation for methods inherited by subclasses. This pull request incorporates an improved version of this post-processing as part of the processingrefBuild.sh script. The post-processing requires two small and easily available binary dependencies (jq and sponge). Since the original doclet process already required calling npx for prettifying the JSON files I have also incorporated the call to npx in the shell script, added checks and warnings regarding all three dependencies to the script, as well as added a note about them to the README.

I expect to make some more small changes to the sound library specific portions over the coming month, so this pull request is really just an invitation for review/comments of whether this could/should be merged at all.

As a side-note: the refbuild script prints "Removing previous version of the ref..." to the shell before building the new javadoc, even though no actual deletion of pre-existing json files in the output directory happens. The sound library reference requires all pre-existing json files to be cleared in order to create valid documentation, so I have had to add a separate rm call to clear the sound-specific files.