------
- updates:``ami``: Custom CentOS 6 kernel repo added, support for >32 vCPUs
- feature:``ami``: Chef 11.x client + berkshelf
- feature:``cfncluster``: Support for S3 based pre/post install scripts
- feature:``cfncluster``: Support for EBS shared directory variable
- feature:``cfncluster``: Support for C4 instances
- feature:``cfncluster``: Support for additional VPC security group
- updates:``ami``: Pulled latest NVIDIA driver 340.65
- feature:``cli``: Added support for version command
- updates:``cli``: Removed unimplemented stop command from CLI