Fix TOC to work in frontend and show no preview in backend
Merge pull request #63 from Kunstmaan/fix/fix-toc

Fix TOC to work in frontend and show no preview in backend
changed abstractpage to haspagepartinterface
changed exception
added use statement
use standard invalidargumentexception
Merge pull request #64 from Kunstmaan/fix/pagepartadmin

Fix/pagepartadmin
Merge branch 'master' into 2.2