Merge pull request #417 from ASPIRINpp/master

fix: #133, #418, #400
Merge pull request #433 from ASPIRINpp/master

Fix: #425, #423
Added option to flush log entries
Updated translation files (translate.humhub.org)
Regenerated translation files
Fixed wrong save flash message #409
Added gallery support for uploaded images #385
Merge branch 'master' of https://github.com/humhub/humhub
Fixed (Not able to comment under IE11) #325
Overwritten original bootstrap focus class for navbar entry
Fixed copy & paste behavior for posts and comments in Firefox, Webkit and IE #325