[MOD] make admin dependency icon to use icon set

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53018 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] better positioning of preference dependency alert

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53019 b456876b-0849-0410-b77d-98878d47e9d5