scheme and subnet support for Load Balancers ( for VLAN support )

[ Ref # 404 ]
updated the ELB version of API
Update 'getEC2Provider'
return name and description for VPC
Fixes for load balancer listeners from ELB API version changes - 2009-05-15 -> 2012-06-01.
Merge branch 'vpc-support' of github.com:TheWeatherCompany/dasein-cloud-aws into vpc-support
Merge branch 'develop' into vpc-support
Added providerSubnetIds to load balancer. Reworked LB scheme->type.
Merge pull request #1 from TheWeatherCompany/vpc-support

Vpc support - ref #425