Bump start point for custom classes in kryo serialization to 65536.

Doubt we would every use that many, but 8192 was bugging me.  Better to be future proof - a higher count shouldn't hurt things.
Add some javadoc.
Commented out toString execution of traversal optimizations.

This causes early evaluation in the debugger and then really crazy stuff starts happening.
Add a Traversal optimizer for PartitionGraphStrategy.

The optimizer adds HasStep with partition logic in it and auto wraps all vertex/edge instances in a Strategy wrapper.
Add a todo comment around strategy.
Change scope of EntrySerializer - not needed publically.
Merge remote-tracking branch 'origin/master'