adds ability to silence notifications

* call ofxNotify::draw(false)

this will only keep track of messages, but not draw them on screen.

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
cleanup

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
Merge pull request #1 from tgfrerer/master

合并原作者更新