pithos: Refactor Gunicorn conf file

Remove shared memory file, /dev/shm/wid, and use a
shared memory mapping instead for the Gunicorn worker
ID bookkeeping.
pithos: Make pithos.conf.py Synnefo wide accessible

Rename pithos.conf.py to gunicorn-archipelago.py and move it
to snf-webproject under the directory gunicorn-hooks to
make it wide accessible.
snf-deploy: Update Gunicorn conf file

Update Gunicorn conf file and relevant files.
pithos: Remove obsolete Gunicorn worker
docs: Update upgrade doc for 0.16
docs: Update Debian installation guide
docs: Update CentOS installation guide
docs: Fix typo
admin-ui: Modify html templates

- Modify html structure of filters.
- Modify html of checkboxes, radiobuttons and arrow-buttons
- Add a dropdown list with all the available filters in each page
- Minor rewording
admin-ui: Add more style rules

- Modify style of filters
- Add style rules in order to change the state of checkboxes,
  radiobuttons and arrow-buttons by css
- Fix rendering bugs noticed in Firefox
admin-ui: Update icon-font and corresponding files
admin-ui: Modify filters javascript code

- Add the ability to choose the visible filters in standard view
- Refactor filters functionality
- Store user's preferences regarding filters in cookie
- Store the state of main tables in local storage
- Refactor the way the user can switch between compact and standard
  view of filters
- Refactor the way the state of checkboxes, radiobuttons and
  arrow-buttons changes.
admin-ui: Add generated css files
docs: Change snf-dispatcher group to archipelago