External process for hibernate code generation cannot work with 3.2-3.5 and 3.6 at the same time

If you compile Hibernate Tools against 3.5 it cant run on 3.6; and if you compile against 3.6 it can't run on 3.5 (even though the code is source compatible)

Since we want to support Hibernate JPA 2 we need to upgrade to 3.6 but then we cannot at the same time provide the "external process for hibernate code generation" since that will almost always collide with users classpath and thus you get errors like:

java.lang.IncompatibleClassChangeError: Found class org.hibernate.cfg.Mappings, but interface was expected

Because the interface Mappings in 3.6 is a class in 3.5 and previous versions.

I don't know a good way to work around this thus for now we will have rollback JBIDE-6423