Interfaces for creating new data importers.

### Create a new Importer

1. Create a new module and set `Import API`, `File System API` and `Utilities API` as dependencies.
2. Create a new builder class, which implements:
   - FileImporterBuilder (files)
   - DatabaseImporterBuilder (databases)
   - WizardImportBuilder (web and more complex scenarios)
3. Add @ServiceProvider annotation to your class to declare you are implementing an Importer service. Put `FileImporterBuilder.class` as the annotation service parameter for text and XML, `WizardImportBuilder.class` for wizards and `DatabaseImporter.class` for databases.
4. Create a new importer class,which implements `FileImporter`, `DatabaseImport` or `WizardImporter`.
5. In the builder, return a new instance of your importer in the `buildImporter()` method.
6. For settings UI, create a new `ImporterUI` implementation and add the @ServiceProvider annotation to it.

To let your import task be cancelled and its progress watched, implement `LongTask` interface. Add `LongTask API` as dependency to your module first.

See HowTo write an import for more details.