CLI renaming and phrasing (#385)

* Minor naming and phrasing changes from UX review

* category-selection-limit -> max-category-items
* Indicate load may taking a long time
* program -> command (for launch, prepare)
* debug -> verbose
* flask-debug -> debug

* Developer mode for debug

verbose on
open browser off

* move examples from epilogue to prefix

server/app/rest_api/rest.py

@@ -112,7 +112,7 @@ class ConfigAPI(Resource):
                     "dataset": current_app.config["DATASET_TITLE"]
                 },
                 "parameters": {
-                    "category_selection_limit": current_app.data.category_selection_limit
+                    "max_category_items": current_app.data.max_category_items
                 }
             }
         }