bump version to 0.5.1

bump version to 0.5.0

bump version to 0.4.4

bump version to 0.4.3

bump version to 0.4.2

README: some edits/additions

bump version to 0.4.0

README: Other important information edits/clarification

README: minor edits

Update README; bump version to v0.3.1

As of this writing, I'm actually not done testing it with beta 9 yet,
but it has gotten far enough in the installation process that I would
be very surprised if it fails.

I'll wait until testing is done -- I think it should take less than
an hour -- then, if it succeeds, I'll merge this into the main branch
and release it.