LIBCLOUD-571 subnet-filters for ec2 driver

Closes #306

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
LIBCLOUD-572 internet-gateways-filters for ec2 driver

Closes #307

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Merge branch 'trunk' of https://git-wip-us.apache.org/repos/asf/libcloud into trunk