Minor Bug Fixes:

* FastTrackTools now are more careful in join to not increment the
    VC for a gc'd thread tid.
* ArrayStateFactory now forgets the right state when two are created
    lazily.
* FineArrayState now checks to ensure the expected value is there
    before writing.
* FastTrackTool had a readEpoch in place of a writeEpoch in the
    fastpath for writes.
Merge branch 'master' of https://github.com/stephenfreund/RoadRunner