Rename package from 'nw' to 'novelwriter' (#868)

* Rename nw folder to novelwriter
* Rename nw to novelwriter in auxiliary files
* Rename nw to novelwriter in main app source
* Rename nw to novelwriter in tests
* Make setup script for pdf docs less spammy

novelWriter.py

@@ -17,5 +17,5 @@ except Exception:
 os.curdir = os.path.abspath(os.path.dirname(__file__))
 
 if __name__ == "__main__":
-    import nw
-    nw.main(sys.argv[1:])
+    import novelwriter
+    novelwriter.main(sys.argv[1:])