Convert merger functions to Strategy classes.
_mergers.py -> strategies.py
Basic infrastructure for schema generation
Overwrite.get_schema()
Append.get_schema()
Version.get_schema()
Basic ObjectMerge.get_schema()
Add nested updates to schema in object merge.
Raise TypeError if schema is ambiguous.
Add warning regarding weakly defined schemas
Add TODOs
Use Limit in schema for Version strategy.
Add support for version metadata schema.
Default strategies now work in get_schema()
Merge branch 'add-schema-generation'