find-vm had the annoying property that on `/usr/libexec/java_home` based systems (Such as macs), trying to find the location of an unknown VM version just gave you the default, meaning `ant test.javac25` would run on 24. Now, it errors.
javac8 has a bizarre dependency situation: we need the stubs in src/stubs there to compile, but if they are there
at runtime during a test run of javac8, they take precedence over the JDK's javac (because we include this
as a separate cp entry, and thus it is not a bootclasspath item), and messes everything up.
The fix is to tell eclipse to compile various src/X folders to different 'bin' targets, which required
an update to ivyplusplus as well.
also it was just broken in general, fixed that too :)