DescribeSubnets: Added support for 'filters' parameter.
DescribeSubnets: Added support for 'filters' parameter. (fixed NotImplemented error message)
CreateSubnet: Added VPC ID validation.
Add multi-region support to EC2 Instances
Add multi-region support to Autoscaling
Implementation for ModifySnapshotAttribute and DescribeSnapshotAttribute.
Get region names in a backward compatible way
Change test_regions.py to work with old boto versions
Merge pull request #173 from hltbra/multi-region

Add multi-region support to EC2 Instances, Autoscaling Groups & LaunchConfigurations
Merge pull request #170 from DreadPirateShawn/DescribeSubnetsFiltering

DescribeSubnets: Added support for 'filters' parameter.
Merge pull request #172 from DreadPirateShawn/CreateSubnetVPCValidation

Create subnet vpc validation
Merge pull request #175 from DreadPirateShawn/SnapshotAttributes

Implementation for ModifySnapshotAttribute and DescribeSnapshotAttribute.