* changes:
NoteDb: Check change message author matches update author
Create BatchUpdates using InternalUser where appropriate
NoteDb: Add test for sequence of comment update operations
Rewrite updating comments in NoteDb
AbstractChangeUpdate: Set author/committer in superclass
Support ChangeUpdates from InternalUser
Start tests for ChangeRebuilder
Rewrite ChangeRebuilder to better use NoteDbUpdateManager
Rewrite AbstractChangeUpdate to not extend MetaDataUpdate
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