Draft NOTES for 1.13.0

@mglukhovsky can you please review?

@danielmewes @Tryneus @mlucy @danielmewes @neumino @srh Please also take a look to make sure I haven't mis-characterized some of your fixes.
If we write `r.args` below I think we should write `r.changes` here.  Also, we usually call them commands rather than methods.