suggest common imports (issue #1550)

git-svn-id: http://processing.googlecode.com/svn/trunk@10814 fe3ceab9-de17-3b67-bb2e-7d58edd5e4d6
prevent error when sketch line not located from Commander (issue 1548)

git-svn-id: http://processing.googlecode.com/svn/trunk@10815 fe3ceab9-de17-3b67-bb2e-7d58edd5e4d6