ENG-5599: 2gb everywhere.
Merge branch 'master' into ENG-5599
Merge pull request #1030 from VoltDB/ENG-5599

ENG-5599: 2gb everywhere.
Revert "Update books for new heap recommendations and changed default."

Remove 3.7 books accidentally committed to master rather than branch.

This reverts commit 0b5213cf9e6bacaae169d2dc4b7f0938b7070a26.
Merge branch 'master' of github.com:VoltDB/voltdb