logs: move resources under cfdsl.logs.
logs: no need for cfdsl.logs.Logs utility class.
rds: move resources under cfdsl.rds.
iam: move resources under cfdsl.iam.
cloudtrail: move resources under cfdsl.cloudtrail.
ec2: move straggler class under cfdsl.ec2.
test: reorganize tests in logical files.
rough support for AWS::Kinesis::Stream.
rough support for AWS::EC2::CustomerGateway.
rough support for AWS::EC2::DHCPOptions.