fix list-items being added as top-level sections when breaking out of lists
fix list-items being added as top-level sections when breaking out of lists

bustle/mobiledoc-kit,bustlelabs/mobiledoc-kit,bustlelabs/content-kit-editor,YoranBrondsema/mobiledoc-kit,bustle/mobiledoc-kit,bustlelabs/content-kit-editor,bustlelabs/mobiledoc-kit,bustlelabs/content-kit-editor,YoranBrondsema/mobiledoc-kit,bustle/mobiledoc-kit,bustlelabs/mobiledoc-kit,YoranBrondsema/mobiledoc-kit,bustle/mobiledoc-kit