Testing adding user-data support to Packer
Convert string to byte array
scripts: full SHA1 in build, not short
provisioner/salt-masterless: nice error even if bad exit status

/cc @rgarcia
Fix packer test
packer: machine readable output for available commands
command/build: machine-readable artifacts
packer/rpc: ui.Machine works over RPC properly
command/build: use the real artifact string in machine readable
website: document machine-readable types
Merge pull request #253 from phobos182/master

builder/amazon/common: added passing UserData to goamz.
Update CHANGELOG
builder/amazon/common: support user_data_file
builder/amazon/all: support user data file
website: document user data stuff