Added CentOS 6.5 x86_64 box

This includes no provisioning software but does include
developement tools such as gcc, make, etc. VirtualBox Guest
Additions 4.3.4 is preinstalled.
Updated the CentOS 6.5 box.

  * SSH keys are now generated on first boot.
  * IPv6 is now enabled.
  * Results of the build can be emailed to you. See notes in README.
  * Remove some extra packages that "Development Tools" throws in
    there. See the packages diff for full information.
  * The yum cache now ships empty.
  * yum-utils is now maintained in the build. It is a collection of
    useful tools to get more information about your local packages.
  * Many of the logs in /var/log are cleared to not confuse with
    your debugging.
Merge pull request #239 from casr/master

Added CentOS 6.5 x86_64 box