Switch how series plugin stores reference to backlog plugin. fix #2207
Implement a timed dictionary to use in caches
Switch cached_input to use timed dict and fix tests for it
Fix cookies plugin and switch it to using timed dict cache
Fix rss unit test
Switch a few more plugins to json schema
Add a note in developer docs about the schema test in the suite
Fix more plugins reference to backlog
Fix a few more usages of process_start