Use cm's not-found page
Add log page
Merge branch 'master' of github.com:denkmal/denkmal.org into issue-186

Conflicts:
	library/Admin/library/Admin/Menu/Main.php
Upgrade to CM 1.23
Fix log page layout
Restructure log menu entries
Upgrade to CM 1.23.1
Merge pull request #186 from njam/issue-186

Add error log in admin