Updates to support new LaunchConfiguration properties and create options

Support new LaunchConfigurationCreateOptions from
TheWeatherCompany/dasein-cloud-core#49
Add support for creating and getting LaunchConfigurations with:
AssociatePublicIpAddress, EbsOptimized, InstanceId, and
BlockDeviceMapping.

Also fixed some whitespace inconsistency.

Ref #69
Update VolumeAttachment class changes

Ref #69
fix a few bugs related to new launch config options

BlockDeviceMapping = BlockDeviceMappings
Also must spec VolumeSize with SnapshotId if specifying IOPs
Ref #69
Merge pull request #70 from TheWeatherCompany/enhancement-69

#69 - Support for Additional Launch Configuration options - AssociatePublicIPAddress, IOOptimized, virtualMachineId, and VolumeAttachments