core: exporters: owl2: preserve newlines in exported literals

Avoid removing newlines from literal values and export them as
entered by the user. This removal was mostly a hack from the time
when entity IRIs where entered with newlines in them for formatting
purposes, and automatically-generated annotations like rdfs:label
where also getting these newlines.

eddy/core/exporters/owl2.py

@@ -698,7 +698,7 @@ def getOWLApiAnnotation(self, annotation):
         if annotation.isIRIValued():
             value = self.IRI.create(str(annotation.value))
         else:
-            lexicalForm = annotation.value.replace('\n', ' ')
+            lexicalForm = annotation.value
             if annotation.language:
                 value = self.df.getOWLLiteral(lexicalForm, annotation.language)
             else: