inception-project#4058 - Cannot export texts containing certain chara…

…cters as UIMA CAS XMI

- Enable sanitziing of illegal characters on export for XMI formats
- Added option to control if sanitation happens or not
- Updated documentation of XMI formats

inception/inception-export/src/main/java/de/tudarmstadt/ukp/inception/export/DocumentImportExportServiceImpl.java

@@ -99,7 +99,6 @@
 import de.tudarmstadt.ukp.inception.export.config.DocumentImportExportServiceAutoConfiguration;
 import de.tudarmstadt.ukp.inception.export.config.DocumentImportExportServiceProperties;
 import de.tudarmstadt.ukp.inception.export.config.DocumentImportExportServiceProperties.CasDoctorOnImportPolicy;
-import de.tudarmstadt.ukp.inception.io.xmi.XmiFormatSupport;
 import de.tudarmstadt.ukp.inception.schema.AnnotationSchemaService;
 import it.unimi.dsi.fastutil.ints.IntArrayList;