Merge branch 'release-0.14' into develop
Introduce new Pithos variables

Introduce new Pithos variables for selectable storage backend.
Extend Ganeti create script

Include new Pithos variables for selectable storage backend to Ganeti
create script.
Extend pithcat for selectable storage
Add default values for Pithos backend and RADOS

Set default values for Pithos storage backend type, RADOS conf file,
RADOS map and block pools.
Update documentation
Merge branch 'feature-pithos-backend-storage' of https://github.com/cnanakos/snf-image into develop
docs: Add section to install snf-image on CentOS
docs: Update installation guide to use root prompt
Don't let sgdisk align when creating partitions

In order to extend a partition we need to remove and recreate it. If the
partition was misaligned then the image is to blame. snf-image is not
allowed to change the starting sector of the partition since this will
destroy the file system it hosts. In order to make sure this does never
happen we need to set the sector alignment multiple to 1.
docs: Update the sample images links

* Add (k)ubuntu 14.04 and remove 13.10
* Add Oracle Linux
* Remove Debian Squeeze
* Add OpenBSD 5.5 and remove 5.4
Update the AUTHORS list

Add Chrysostomos Nanakos to the list of snf-image authors
Bump version to 0.15rc1

Add multiple version files to automatically update the docs version too.
We need devflow 0.13rc1 or later for this to work
Update ChangeLog for version 0.15rc1
Add pithos backend version check

Synnefo version 0.15.1 has introduced a selectable storage backend
for Pithos, resulting in necessary changes to the ModularBackend class.
In order to keep backward compatibility with older Synnefo versions,
we check the Pithos backend version and instantiate the ModularBackend
class appropriately.
Bump version to 0.15rc2

Update Changelog and version files.
pithcat: Remove default option values

Handle better possible backend options and require necessary
ones by printing appropriate error messages.
Fix typos in error messages and docs

Replace all references of `environmental variable' with `environment
variable'
Bump version 0.15rc3

Update ChangeLog and version files
Merge branch 'release-0.15'