added logo and footer;also converted menu links to buttons

This PR provides the following enhancements to the app
* added logos and links to the CloudFoundry and Docker communities, so a click on the logo takes user to the main web page of the community.  
* added favicons (the little icons that show up on the browser tabs) for the CloudFoundry and Docker communities.
* added footer
* moved update and version info to the footer for the interests of yielding more prominent spaces to the charts and tables
*  pushed linked menu items up to the banner area after moving title toward the left.  Again, this was also for yielding more prominent spaces to the charts and tables.
* converted linked menu items to buttons.