Specs for existing `Fog::Bin` interface

Prepartion for fog/fog-core#105
Detailed checks for `Brightbox` class
Adds openstack_region parameter to OpenStack Identity Service
Moved StormOnDemand to its own gem
[opennebula] lazily require opennebula gem

closes #3295
Moving Rackspace logic to fog-rackspace
[storage|aws] more redirect tweaks
[aws|auto_scaling] Add PlacementTenancy attribute for launch configuration
Disable rackspace until fog-rackspace#10 is fixed.
[DigitalOcean] Helper methods for flavor,image,region,ips
[AWS|Storage] make s3 IO based uploads retryable again

requires that excon be updated to support retrying request_block based requests
Add AssumeRoleWithSAML support for AWS
Ensure that if the aws credentials requests requiring the signature fail
Fix link to documentation
Fix code style
Add simple test
Fix style
Moved to Fog::Core
fixed backups in DigitalOcean
[AWS|Storage] allow signature version to be set to 2 (WIP)