Use the measurement info to write each line of text separately, thus
respecting word-wrapping and newlines.
Fix up the comment for scene_obj_render() while we are here.
Since a lineedit does not support alignment, add a special case to just
display the text if there is no measurement. This happens assuming the
lineedit is initially empty.
Signed-off-by: Simon Glass <sjg@chromium.org>