* initial check-in of working auto block size tuning for import. Needs clean-up.
* partial fix in this branch to enable testing, awaiting better fix in different branch.
* move pacing code from findIdleSender to AutoTuneThread object.
* move pacing code from findIdleSender to AutoTuneThread object. clean up dead code. add comments about algorithm.
* edits to algorithm discussion
* correct logging level. add CHANGELOG entry.
* update comment concerning proper usage of shutdown()
* initialize new static member MaxBatchSize. Correct sendCsvBuffer() call to addPeriodByteCount() since _outputBuffer drained by sendData().
* remove redundant semicolons. add new static member MaxBatchSize.
* move MaxBatchSize to ImportHelper so both ImportFeature object and AutoTuneThread object can access it.
* minor updates to comments and statics
* add pacing discussion to import manual page
* minor edit