post-processor/compress Add support for artifact compression.

parallels-iso: allow absolute output directory.

Fixes [GH-1466]

Add the cleanup when the process of EBS AMI interrupted

Merge branch 'add-spot-instance-support' of github.com:henrysher/packer into henrysher-add-spot-instance-support

Conflicts:
	builder/amazon/common/run_config.go
	builder/amazon/ebs/builder.go
	builder/amazon/instance/builder.go

Conflicts:
	packer/config_template.go
	website/source/docs/templates/configuration-templates.html.markdown

common: Fixes #1114, Adds upper and lower as filters for the template engine.

Merge branch 'add-chef-environment' of github.com:cfortier2/packer into cfortier2-add-chef-environment

Conflicts:
	provisioner/chef-client/provisioner.go

[GH-1388]