Populate the USERS metadata for windows images

For windows images check the appropriate registry keys to find out
the system users
Bump debian version to 0.3-1wheezy
Make use of devflow building system
Merge branch 'master' into develop
Bump version to 0.3next
Move mount/umount from image to os_type module
Code Cleanup

 * Prefix all private methods with _
 * Write missing docstrings
 * Move all public methods above the private ones
 * Add module docstrings where missing
 * Define source code encodings on all modules
Monkey-patch pythondialog to support form boxes
Comply with kamaki 0.9

 * Change the authentication everywhere to use clouds
   (authentication URL and token pairs)
 * Add menu entries to manage clouds
 * Add an extra -a option in snf-image-creator to allow the user to
   specify authentication URLs
Add --cloud option in snf-image-creator

This options can be used to get the authentication URL and token
from a saved cloud section in the kamaki configuration file
Change the metadata file format to json

When registring an image, use the information returned by the
kamaki register method to construct the metadata file.

When dumping the image to the local filesystem, store the image
properties and the disk-format info in the metadata file.
Update the ChangeLog

Make the ChangeLog comply with the latest changes
Create a new cloud wizard page

Make the cloud selection wizard page an instance of WizardMenuPage
Minor cleanup in dialog_wizard

 * Move all common WizardPage variables to the base class
 * Give more sensible names to some variables
 * Make Wizard compute the title for all WizardPages
Merge branch 'feature-synnefo-0.14' into develop
Remove all referencies to words like ~okeanos

In the documentation and the printed messages, remove all references
to ~okeanos, pithos or cyclades.
Merge branch 'develop'
Bump version to 0.4
Bump development version to 0.4next
Update depencencies for version 0.4