Bug fix - Update buffer title when updating the note.
Bug fix - Update buffer title when updating the note.

Bug fix for dc7789c1f2f3b49c6c601a8e94543402266a9ae2

I forgot that when editing the note of course the first line could
change and therefore we need to update the buffer title.

References #75

sanchon/simplenote.vim,sanchon/simplenote.vim,mrtazz/simplenote.vim,mrtazz/simplenote.vim