Links now have reasonable performance, so remove freebie
Running optimistic freebies so we know when they start to pass
Documenting a bit about the optimizer
Fixing bug in agents dying while their agentset is being processed

This addresses a case where some agent, A, would ask some agent, B, to
die while iterating over an agentset that contains both A and B.
Previously, B would still run the command block, even while dead.  Now,
when a shufflerator detects an item that does not meet its criteria for
validity, that item is ignored.  This behavior is compliant with JVM
NetLogo's behavior.
Fixing bug in which turtle shape gets used

  * Bumps to newer version of Headless with simple test for bugged scenario
  * Adds testing for the Wolf Benchmark model, which helped to catch the bug
  * Adds dump for Wolf Benchmark
  * Includes whining comment from yours truly!