The TeplMetadataManager API has been re-worked.
The TeplFileMetadata class has been replaced by
TeplMetadata, the latter no longer
depends on TeplFile.
The tepl_file_get_file_metadata() function has been
removed.
The tepl_tab_load_file() function no longer loads the file metadata (but it was anyway an implementation detail).
The TeplAbstractFactoryVala class has been removed,
because it's possible to manually manage GObject references in Vala.