Add flexible IP pool/address handling.
builder/digitalOcean: use names/slugs as well as IDs for image/region/size
Optional parameters in vSphere post-processor.
datastore, vm_folder, and vm_network options can be omitted.
builder/amazon: alphabetize some things
Merge pull request #1091 from mkuzmin/vsphere-parameters

post-processors/vsphere: Optional parameters in vSphere post-processor
post-processor/vsphere: comments and style
Update CHANGELOG
Merge pull request #1089 from rasa/use-slugs-for-digitalocean

builder/digitalocean: use names/slugs as well as IDs for image/region/si...
Update CHANGELOG
Merge pull request #919 from nebula/manage_floating_ips

[OpenStack] Add flexible IP pool/address handling.
website: openstack docs
Update digitalocean.html.markdown

tiniest of typos
builder/openstack: support a tenant ID
website: update openstack docs