Slave goes through 'switchToSlave' process on every 'masterIsElected' event
Updates changelogs for 1.9.9 with last batch of changes
Merge pull request #3217 from lutovich/1.9-slave-epoch-mismatch

[1.9] Slave goes through 'switchToSlave' process on every 'masterIsElected' event
Tagging for version 1.9.9
Back to development version.
Updates poms to 1.9.10-SNAPSHOT
Disable the OmitStackTraceInFastThrow JVM feature

Also make sure that the wrapper.conf files are otherwise identical.
Merge branch 'chrisvest-1.9-disable-omit-stacktrace' into 1.9-maint