(cherry picked from commit b343d634)

(cherry picked from commit 65797f04)

(cherry picked from commit 8a315b1e)

Whoops: Changes in error message and logging

(cherry picked from commit d4d6878b)

(cherry picked from commit 2d873eae)

(cherry picked from commit 4e740d0c)

(cherry picked from commit 5ebbf65c)

TestQuestionPool: Fixed image type detection according to Mantis issue #20395 (resulted in broken imports)

(cherry picked from commit a87074d8)

(cherry picked from commit 724dfc97)

(cherry picked from commit be73304d)

(cherry picked from commit 30b60001)

(cherry picked from commit 332bf5fe)

(cherry picked from commit 0685886a)

(cherry picked from commit 8b76e232)

(cherry picked from commit b3c9cd9a)

fixed bug 20549: Signature of \ilUIHookPluginGUI::checkGotoHook not compatible with call in \ilStartUpGUI::_checkGoto

(cherry picked from commit 9ea1dc77)

(cherry picked from commit 0626c1cd)