Update README.md.

Things have moved on in BEEBS, and the README has fallen behind.  This
should bring things up to date.

ChangeLog:

	* README.md: Update for latest state of BEEBS.
Merge branch 'update-readme' of github.com:T-J-Teru/beebs into T-J-Teru-update-readme
Merge branch 'T-J-Teru-update-readme'