provide title attribute for generated icons and rename gray to grey, re #2881

git-svn-id: svn://develop.studip.de/studip/trunk@26095 c5b85792-5220-0410-ad23-ed5b6b8ad999
adjust icon tool's bootstrap to changes on trunk, re #2881

git-svn-id: svn://develop.studip.de/studip/trunk@26096 c5b85792-5220-0410-ad23-ed5b6b8ad999
provide a svg file with both the icons and the arrows, re #2881

git-svn-id: svn://develop.studip.de/studip/trunk@26097 c5b85792-5220-0410-ad23-ed5b6b8ad999