Also add in Hamlib-related PYTHONPATH information.

README.md

@@ -83,6 +83,10 @@ make
 sudo make install
 ```
 
+You will also need to append the Hamlib `bindings` and `bindings/.lib` directories to the `PYTHONPATH`:
+
+   `export PYTHONPATH=$PYTHONPATH:/path/to/hamlib/bindings:/path/to/hamlib/bindings/.lib`
+
 Contact
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