Check if image already exists before doing anything else on GCE.

Remove bucket_name from GCE config.

Fixes #1732. Forgot to do this in 23c947ac.

This fixes #1729.

Use an index loop as range loops over copies, not references

Upload VMX to ESX5 after editing

post-processor/vagrant: check if vagrantfile_template exists

added ssl_verify_mode parameter to chef-client provisioner

change ordering of ssh connection IP for amazon. fixes #1559

Use DigitalOcean image ID for artifact Id()

Test for user variables in vagrantfile_template [GH-1125]

Parallels: Fixed issue #1667

Update the getting started docs with Amazon changes

The AMI that was previously listed before this change no longer exists.

Fixed typo

Fixes #1637

fix googlecompute oauth dependency

Use sudo only if prevent_sudo is not set

fix build name ConfigTemplate processing [GH-858]

Add default nodename for chef-client

Fixes Docker communicator mishandling of symlinks in UploadDir()

Allow none checksumtype for qemu builder

fix digitalocean v2 api content-type when using json

When using disk_image CD-ROM not needed

Use consistent escaping for ovftool uri creds

Create GCE image from persistent disk instead of from a tarball.

The new flow:
1) Provision the instance
2) Tear down the instance, but keep the boot disk
3) Create an image from the disk
4) Tear down the disk

The step to update gcloud is no longer needed, since gceimagebundle isn't used anymore.
Fixes #1507 and addresses https://github.com/mitchellh/packer/issues/1447#issuecomment-61610235.