Added YAML config support.

- Manifest format parsing is now checked by the file extension ie: .json, .yml or .yaml.
- load_yaml in common/tools is the same as the json version.
- schema checking of manifest still passes (and fails appropriately) like the json manifests.
- I've also included a sample yaml config based off of the debian test json manifest.
Add in jessie.
Manifest files for Squeeze (now oldstable).
Add security.debian.org to apt sources.list
Set grub console to text, and set system console to hvc0 on grub cmdline.
Move volume imports in fs/__init__
Move import statement
Re-raise the catched exception after rollback
Remove unused real_device_path
Unset unlinked_device_path after use
Minor adjustments in pkg code
Remove default argument (info={}) in tasklist.run
Fix check_ordering of succ. (it always succeeded)
Remove load_json fn from manifest
Set volume dev_path to None when detaching
When detaching unset single partition dev_path
add azure provider
Correct merge/rebase. Fix handling of console to hvc0. Try and pre-seed cloud-init.
ASwitch manifests ot explicitly use Ec2 for metadata. Swap S3 to use a 4GB root FS.
Fixed import style.