Expose java.lang methods if directly specified by Types

Don't ask me exactly how, because I didn't manage to reproduce it in a test case, but.. 

While bootstrapping Furnace SE and adding my own custom AddonRepository, I end up with a situation where a AbstractMethodError is thrown from here:
https://github.com/forge/furnace/blob/master/container/src/main/java/org/jboss/forge/furnace/impl/graph/AddonGraph.java#L16

It happens when both vertex.getVersion() and version is a Proxy in the version.compareTo(vertex.getVersion()) call. 

Looking at the code, the Proxy does not handle compareTo even tho the specified type to enhance is Comparable. This patch fixes that.