v3.1.0

[3.1.0] - 2016-01-26

Note: Minor breaks in backwards compatibility

Added

• Added the ability to work with NAT gateways. Requires a custom Lambda function. See README.md.
• Added AWS::CloudFormation::WaitCondition and AWS::CloudFormation::WaitConditionHandle to support pausing
  for resources to do things.
• Added support for the Fn::GetAZs function
• Added in VPN support

Changed

• Improved EIP model to better handle VPC vs Classic EIPs. Changes are backwards compatible, but
  existing methods are now deprecated.
• Most functions updated to use Token[ConditionRef] instead of Token[String]
• Changed how implicits are handle in creating AWS::EC2::Route to simplify the code