Fix baby sitter sorting of the children nodes.

The children nodes are ephemeral sequential nodes, but their prefix are
different. To sort them based on creation order, we have to sort by the
ephemeral sequence number part, not the whole string.
Minor fixes to CoreZK.get*FromChildName() and fix TestBabySitter.
ENG-6150 clone and activate only active elastics post-truncate
Merge pull request #1278 from VoltDB/babysitter-sort

Fix baby sitter sorting of the children nodes.

r=izzy
Add final format of 4.2 books.
Merge branch 'master' of github.com:VoltDB/voltdb
Merge pull request #1279 from VoltDB/ENG-6150-elastic-truncate-activate

ENG-6150 clone and activate only active elastics post-truncate
Crash globally on hash mismatches.

Crashing the SPI leaves the inconsistent nodes up and causes the cluster to
diverge.
Merge pull request #1282 from VoltDB/hashmismatch-crash

Crash globally on hash mismatches.
refresh the baseline
Merge pull request #1283 from VoltDB/quick-planer-baseline-change

refresh the baseline r=pmartel
ENG-5975: Cleanup and polish.
Merge remote-tracking branch 'origin/master' into ENG-5975-rejoinfail