Remove 'monolithic' build targets (jar, etc).

This is to avoid users accidentally attempting to build the old
monolithic jar.

The change here is not a full purge of the old monolithic build but
just aims to remove the make interfaces which could attempt a monolithic
jar build.

I also removed some other stuff which should be unused.
Merge pull request #919 from jordansissel/disable-old-monolithic-jar-builds

Remove 'monolithic' build targets (jar, etc).