builder/digitalocean: use HTTP proxy if in env
Update CHANGELOG
post-processor/vagrant: process output path properly
builder/virtualbox: export to ovf or ova (default ovf)
packer: postProvisioner should be postProcessor
packer: remove keep_input_artifact prior to sending to build [GH-310]
Merge pull request #309 from jsiebens/virtualbox_ova

builder/virtualbox: export to ovf or ova (default ovf)
Update CHANGELOG
website: document formats feature
builder/virtualbox: fmt
packer/plugin: set TCP keep-alive on connection
v0.3.3
update version for dev