iterator close now returns/completes immediately.  made operation that claims the close a tad more robust against known race condition.
doubtful this does anything.  env free was one of two crash points.
add a missing initialization, should not matter, but safer
clean up closing conditions.  previously allowed two threads to potentially delete the same object (bad, matthew.  bad, bad, matthew)
fix RefDec() to clear unit tests.  add casting to atomic operation on void pointer so OSX would compile
Merge pull request #117 from basho/mv-iter-close-fix

Mv iter close fix