Remove outdated files left over from the xen-api repo

Signed-off-by: John Else <john.else@citrix.com>
Add a new README

Signed-off-by: John Else <john.else@citrix.com>
Add missing releases to CHANGES

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #20 from johnelse/update-text-files

Refresh outdated informational text files