* Add threading support to SGX Avian.
* Handle contract verification exceptions using uncaught exception handler.
* Indent uniformly to 4 spaces.
* Add comments for some of the uses of SGX synchronisation primitives.
* Remove non-deterministic classes from Avian (wip).
* Complete integration between Avian and our local OpenJDK fork.
* Revert accidental Avian modification.
* Implements a "blacklist filter" for Avian's system classloader.
* Remove .DSA, .RSA, .SF and .MF files when creating a fat jar.
* Revert more accidental Avian changes.
* Fix breakage with dependencies, and retain Kryo instance.
* Apply blacklisting per thread rather than globally.
* Blacklist java.lang.ClassLoader and all java.lang.Thread* classes.
* Add comment explaining class blacklisting.
* Fix Avian when building without OpenJDK.
* Configure ProGuard to keep more classes for deserialisation.
* Retain explicit return type for secure random function.
* Add sources of random numbers to the class blacklist.
* Blacklist the threading classes more precisely.
* Make SystemClassLoader.isForbidden() static.
* Prevent ProGuard from removing SerializedLambda.readResolve().
* Remove Avian tests involving direct buffers.
