add README.txt

This isn't a plain copy or symlink from README.md
since that is a bit difficult to read due to link formatting.

Additionally this is already updated for version 2,
which the README.md wasn't since it was used as the github info.
add README.txt to Makefile
add info about packages to README.txt
Merge branch 'readme'

see pull request #76

Conflicts:
	Makefile