- Correctly detect deleted files from a Library
- Do not allow export of Library objects
- Add option to not import 'private' objects (those prefixed with "_")
- Store `Library` in `MSysSCCPrefs`, this is currently unused, but can be
used by external tools to store metadata i.e. `LastCheckoutVersion` about a
library
Other changes
- Remove unneeded `InFields` checks, this is checked in `AddField`
- Remove unused `fd` variables
- use `frmOptions` variable to streamline reading control values
This change is