Add AWS::KMS::Alias

[chrisgilmerproj]

AWS just released a new resource that allows setting the Alias on a key:

http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-kms-alias.html

Probably would look like this in troposphere:

class Alias(AWSObject):
    resource_type = "AWS::KMS::Alias"

    props = {
        'AliasName': (basestring, True),
        'TargetKeyId': (basestring, True)
    }

Please add to your next release.

[markpeek]

Thanks!

[chrisgilmerproj]

@markpeek - thanks for the fast turnaround:)