removed a sefety return used to avoid logging entirely.
fix against https://github.com/globaleaks/GlobaLeaks/issues/611
added also store.invalidate to finally kill the memory leak
Merge pull request #176 from globaleaks/fix/memory_leak_2

Tested, good
Added Czech translation
Merge branch 'devel' of github.com:globaleaks/GLBackend into devel
bump to version 2.27.1
enhanced unitTest in notification
restored log functionality, removed by mistake, enhanced log exception report
solved conflict, tested patch, fixed issue https://github.com/globaleaks/GlobaLeaks/issues/613
fixed wrong keyword in Comment default notification template
Merge branch 'bugfix/612_notification' of github.com:globaleaks/GLBackend into bugfix/612_notification