Refs #7553 mpi chunks for can and vanadium
(cherry picked from commit 37cfccb94eb8be5be19ceb4a64376042a38c4939)
Refs #7553 preserveEvents=False agrees with True
(cherry picked from commit e6148fdfc8cd905debe717c369262e5d8379b99b)
Refs #7553 mpi version should not gather all events on first core
Refs #7553 adding warning for resetting preserveEvents
(cherry picked from commit fb6a7a71423838818fcbc587f1fa368d0a0be649)
Refs #7685 check preserveEvents before compressing
(cherry picked from commit 3f0d6a61c0813aca9c39fb09f92f5f9a0521515d)