[IMPR] Improve option handling in flickrripper.py
[IMPR] Improve option handling in flickrripper.py

- improve option handling
- config.py contains all flickr variables. It is not necessary
  to check for existence
- use suggest_help to check dependencies, settings and parameters
  and return if necessary

Change-Id: Ia938dedbc629c646f4f94e7f7d2fc37c9ab10a07

wikimedia/pywikibot-core,wikimedia/pywikibot-core