branding: Common cross app branding setting related to web fonts urls

Introduce BRANDING_FONTS_CSS_URLS setting to support loading of webfont
related css files from custom locations. By default fonts are loaded
from Google CDN servers. An essential utility setting for intranet
Synnefo deployments.

The `undocumented` setting UI_FONTS_BASE_URL is deprecated and no longer
used.
cloudbar: Apply condition on whether or not to load webfont css files
branding: Update branding-settings.conf

include default values and description for BRANDING_FONTS_CSS_URLS
setting.
ui: Remove deprecated setting from ui .conf file
webproject: Use branding webfonts css setting in 403/404/500 templates
cloudbar: Remove debug statements
cloudbar: Include url invalidation parameter based on synnefo version

make cloudbar.{js,css} unique per version to enforce client reload
between previously cached versions after synnefo upgrades.
cyclades: Check that volume type ID is an int

Make `flavor-create` command to check that the given volume type ID is
an integer.
pithos: Set v0 size on Archipelago request
cyclades: Update vncauthproxy requirement

Require vncauthproxy>1.5.
docs: Update docs for 0.16
Add archipelago to Pithos backend dependencies
Merge pull request #214 from cnanakos/release-0.16

Update docs and fix Pithos Archipelago request
Add NEWS for Synnefo 0.16rc1
docs: Update 0.16 upgrade guide
docs: Link v0.16 Chaneglog and NEWS in admin guide
astakos: Fix percentage bar bug in Usage tab
astakos: Wrong module names in MESSAGES_VIEWS_MAP

During the patch 'astakos: reorganize views' the module 'im/views.py'
was transformed into a directory and the code was moved to
'im/views/im.py'. Fix the wrong module names in MESSAGES_VIEWS_MAP
dictionary so that ASTAKOS_*_MESSAGES will be displayed.
branding: BRANDING_FONTS_CSS_URLS not defined

Define the 'BRANDING_FONTS_CSS_URLS' parameter in the config file.
ui: Fix missing cache invalidation param in rivets.conf.js url