chore: add type keyword

fix: ensure subschema errors are not included for undefined obj

fixes #475

fix: ensure nested autoValue is called for modifiers that don't set t…

…he parent

fixes #277

fix: fix "keys" option

fixes #477

fix: don't pass unsupported options to clean

fixes #476

fix: add missing supported constructor option (#490)

fix: update to mongo-object dep that exports cjs

feat: export schemaDefinitionOptions from pkg

fixes #467

feat: improved oneOf support

Thanks to @znewsham for initial work on this

fixes #428
fixes #410
fixes #112
fixes #68

feat: add exported toJsonSchema function