more autorouter feedback

git-svn-id: http://fritzing.googlecode.com/svn/trunk@6812 85f94c43-f63a-0410-9d22-21439860c375
add optional priority

git-svn-id: http://fritzing.googlecode.com/svn/trunk@6813 85f94c43-f63a-0410-9d22-21439860c375