icons: adjust svg files for icon tool, re #2881

git-svn-id: svn://develop.studip.de/studip/trunk@25192 c5b85792-5220-0410-ad23-ed5b6b8ad999
icon tool: fix bugs with non standard sizes, re #2881

git-svn-id: svn://develop.studip.de/studip/trunk@25193 c5b85792-5220-0410-ad23-ed5b6b8ad999