first cut - configuring firewall edgegateway service
posting xml to configure nat service
adding optional fields for nat and firewall service
[vcloud_director] Raise provider-specific exceptions.

HEADS UP: This is a breaking change for anyone rescuing Excon errors.
Add Atmos meta_data request and file_size
configuring load balancer service
element type is not required , when href is provided
renamed service post method according to documentation
Merge pull request #2257 from tobyhede/master

Various atmos enhancements around file meta-data
remove instantiate_vapp_template helper dependencies
require vdc_id as a instantiate_vapp_template param
remove unnecessary helper
- make tags model to use post_undeploy_vapp
- fix syntax error in post_undeploy_vapp method
- remove post_vm_metadata
fix invalid syntax
broke generator code into smaller methods
Merge pull request #2254 from nosborn/vcloud_director_new_errors

[vcloud_director] Raise provider-specific exceptions.
fix situation where the content of the param can be false and not set the attr
Merge pull request #2259 from restebanez/vcloud_director/fix_instantiation_and_tags

Vcloud director/fix instantiation and tags creation
[vcloud_director] Call `end_point` not `endpoint`.
[vcloud_director] Explicitly handle duplicate names.
[aws|compute] remove :host from request parameters
[vcloud_director] Add general queries handler.