Rename txt to README.md to take advantage of GitHub
Renamed VPTOOL-readme.txt
to README.md
. This takes advantage of a nice GitHub feature that automatically renders README.md files into html to provide "in place" user documentation.
Also made a few minor edits to work better with Markdown formatting and added a license header (which is not rendered to html).
Signed-off-by: Mike Thompson mike@openhwgroup.org