Feat: Add isDecompressed() function

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/zip/CityGmlZipEntry.java

@@ -124,6 +124,15 @@ public class CityGmlZipEntry implements Serializable {
         fileSize = size;
     }
 
+    public boolean isDecompressed() {
+        return decompressed;
+    }
+
+    /**
+     * Returns the estimated uncompressed filesize of this entry.
+     *
+     * @return filesize in bytes, -1 if filesize unknown
+     */
     public long getFileSize() {
         return fileSize;
     }