3.1 Feature: remember collapse localstorage

+ Feature: remember collapse localstorage
3.1 Feature: announcement collapse localstorage #2305

+ Feature: announcement collapse localstorage
3.1 ^improve localstorage #2305

+ Add setting: Remove cache
Merge pull request #2305 from 810/feature-crypsis-2

3.1 Feature: remember collapse localstorage