Add line number for warnings

Sometimes the Corona console (at least on Windows) will output debugging information like

“WARNING: Attempting to set property(frame) with nil”

(Many other variations, too.)

My wish: please add the file name and line number that triggers this warning, so that we can easier fix it.

Thanks! [import]uid: 10284 topic_id: 23524 reply_id: 323524[/import]