Vagrant Cloud Post-Processor

fix invalid esx5 path separator in windows

before, this code had joining path elements by filepath module. filepath module generate path string with backslash-joined in Windows. but ESX require path string with slash-joined. it means that this code generate illegal path string in windows. illegal path string raised "Error creating disk".

this patch fixes path separator from backslash to slash in windows. from this, creating disk would succeed without error.

Replace ListServers hack with update ServerById

[gophercloud#168](https://github.com/rackspace/gophercloud/issues/168) has been
patched to not panic on non-existing server id's. If an error is returned,
check if the error is a 404 first before bailing.

builder/openstack: Workaround for gophercloud.ServerById crashing [GH-1257]

Fix openstack ServerById crash

builder/amazon-common: Sort AMI strings before outputting [GH-1305]

Sort AMI names in Artifact.String - fixes random test failures

With go tip, the output from Artifact.String will sometimes be output in a
different order than the tests. Sort the AMI strings before outputting.
See https://travis-ci.org/mitchellh/packer/jobs/28748467 for an example of this
failure.

gophercloud.ServerById is broken in v0.1.0 - it will crash if you feed it a
non-existing server ID (see [rackspace/gophercloud #168](https://github.com/rackspace/gophercloud/issues/168))

Instead, list all servers and iterate over them. If the server id isn't found,
return "DELETED" as a state. Not perfect but it works until next version of
gophercloud is released.

Images link is 404, now must use API

Add gox installation instructions to Contributing

Resolves #1256, add warning mesasge to VMware ESXi driver

Update the qemu example 

builder/parallels: Fixed problems with character when typing boot command

[feature] Support boot command for pvm builder

Parallels-iso errors while removing floppy drive GH-1226

Parallels errors while creating floppy disk GH-1225

Properly escape security_group_id to avoid markdown interpretation of the '_'