Update README.md

Author: MBAigner

README.md

@@ -64,11 +64,15 @@ Edge thresholds:
 ## Project Structure
 
 * ```GraphConverter.py```: contains the ```GraphConverter``` class for converting documents into graphs.
+* ```models```:  contains regression models for layout-independent document processing
+* ```document```: contains the ```DocumentMetaCharacteristics``` class for a layout-independent document processing or managing default thresholds
+* ```merging```: contains the ```PDFTextBoxMerging``` class for an aggregation of layout elements treating the visual rectangle structures of a document
 * ```util```:
-  * ```constants```: 
+  * ```constants```: paths, thresholds
   * ```StorageUtil```: store/load functionalities
-* ```Tester.py```: Python script for testing the ```GraphConverter```
-* ```pdf```: example pdf input files for tests
+  * ```RectangleUtil```: functionalities for visual rectangle constraints
+* ```test/Tester.py```: Python script for testing the ```GraphConverter```
+* ```pdf```: example PDF input files for tests
 
 ## Output Format