removeFormat should remove last line format
removeFormat should remove last line format

closes #649

fraywing/quill,willrowe/quill,quilljs/quill,tim-mc/quill,fraywing/quill,willrowe/quill,voxmedia/quill,sferoze/quilljs,quilljs/quill,sferoze/quilljs,sferoze/quilljs,willrowe/quill,voxmedia/quill,tim-mc/quill,voxmedia/quill,sferoze/quilljs,quilljs/quill