Remove old slot definers from SourceTable
Need to apply aliases in SubSchema implicit conversions
Clean up some tests and make sure they're executable
Switch to new slot definition classes, using aliases for version>0
Don't need to explicitly copy MatchVector slots; they're now in Schema
Test, fix backwards compatibility for old slot persistence
Fix bug in AliasMap that caused replacement of non-aliases.
Improved documentation for slots
Doc fixes from review of DM-419.
Fix oversight in backwards compatibility for slots.
Merge branch 'u/jbosch/DM-419'