[Feature requests] Tabs and persistent storage

I just came across this tool and I am blown away with it.  Especially how simplistic and to the point it is.  Two things I found that would improve the tool were:

1. Multiple tabs.  Doesn't need explanation.
2.  Persistent storage.  If I have a file open and I want to close panwriter, I would like for the file to re-open the next time I open panwriter.  This could also apply to point 1.