EC2 VPC private address allocation - EUCA-9731

A private address is now allocated for instances launched into a VPC
subnet when not specified in the request.

EUCA-9731
EC2 VPC support for management of Network ACL entries - EUCA-9610

Support for create/delete/replace actions for network acl entries.

EUCA-9610
Merge remote-tracking branch 'origin/dev/sjones/EUCA-9610' into testing