init: simplify CloudConfigUnit interface
Merge pull request #245 from jonboulle/units

init: simplify CloudConfigUnit interface
datasource/waagent: add support for WAAgent metadata
azure: add support for azure (via azure agent)
Merge pull request #246 from crawford/master

Add support for Azure
*: add license header to all source files
Merge pull request #249 from jonboulle/license_header

*: add license header to all source files
*: switch to Godeps
Merge pull request #250 from jonboulle/master

*: switch to Godeps
flannel: added flannel support and helper to make dropins

fleet, flannel, and etcd all generate dropins from config.
To reduce code duplication, factor out a helper to do that.