Closes #109, Allow user to clear all saved logs (field note export related)

Implemented a new menu item in cache lists for that
Mising translations #109
Change log update #109
Merge pull request #2530 from Lineflyer/master

German translation and change log update
refactoring: use same package in test as in production
fix #2534: Updating a OC.de cache doubles the cache description
new: strip unneeded markup from OC descriptions