Support EC2 ELB cross-zone load balancing

Allow for EC2 ELB Load Balancers to use the new cross-zone load balancing
feature which better distributes load across all Availability Zones.

http://aws.amazon.com/about-aws/whats-new/2013/11/06/elastic-load-balancing-adds-cross-zone-load-balancing/

Disabled by default unless you add "cross_zone_loadbalancing true" to your ELB definition.
fog errors look different in fog 1.19.0, now they look like "ERROR: Fog::Compute::AWS::Error: Duplicate => The permission \'1500008810-1-1-65535\' has already been authorized on the specified group"
fog -> 1.19.0 and excon -> 0.31.0 to support AWS Cross-Zone load balancing
[aws] Add I2, C3, G2, CR1 instance types, change M3 prices

Also removes non-existent instance type cc1.8xlarge, and adjusts the
number of vCPUs for cc2.8xlarge.
Added new M3 types, added new M3 instance disks, corrected m2.xlarge price
Handle pagination when there are over 100 IAM Certificates