Added vpc_id 

For support of vpc_id attribute in security groups
Added vpc_id
Changed $VERSION to 0.29_01
Merge pull request #37 from Captainkrtek/master

Added vpcId attribute support for SecurityGroupItemType
Added security group tagging support
Missing documentation
Added tagSet support

See bottom of: http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-ItemType-SecurityGroupItemType.html
Merge pull request #38 from hootsuitesteven/master

Added tagSet support for security groups