Update of thirdparty libs and plugins.
Corrected history event for ArticleCreate.
Improved cache module to avoid inconsistent cache states with disabled caching methods.
Added unit tests.
otrs.ArticleStorageSwitch.pl
Define default TTL in Set() of Cache.pm.
Fixed bug#10508 - Fixed selecting of SLA or disabled dropdowns in the customer interface.
Merge remote-tracking branch 'upstream/master' into otrs-master