Update README.md
    
    A few changes in README.md file:
    
    1. Google+ is no longer available for consumer (personal) and brand accounts. I've removed the link to Google+ page as that link is no longer available.
    2. I've added a link to a COPYING file.
    3. Added dots to the end of paragraphs
    
    Reviewed-by: Michal Židek <mzidek@redhat.com>
    Reviewed-by: Pavel Březina <pbrezina@redhat.com>