Changes

Improve gradle builds and debugging (#674)
We now use the java-library plugin in favor of a better
binary interface. This will allow use to specify which
want to keep in our frontend and which are just for
JDA.
 As such the dependencies added with "implementation" will only be
runtime use and are not usable for library extensions directly.
will require libraries using JDA to specify our internal
explicitly rather than relying on us to keep them, allowing
remove dependencies without breaking compilation of other tools.
 (commit: 48a43fc)