docs: Update BlockStorage API guide

According to the Cinder API documentation the GET /snapshots and GET
/snapshots/detail call should return the same detailed results. Cyclades
behave correctly on this matter, but the BlockStorage API guide contains
incorrect and misleading examples.

This commit fixes the above issue.
admin-ui: Use compressed css for production

Compass outputs both extended and compressed css files.
Extended css files are used when settings.DEBUG is True and
compressed ones are used in production mode.
admin-ui: Add generated css files
Merge branch 'release-0.16-admin-css-minified' of https://github.com/AthinaB/synnefo into release-0.16
pithos: Restore PostgreSQL 8.4 compatibility

Change SQLAlchemy statement to generate SQL code that uses ||
concatenation operator instead of the 'concat' function
(inexistent in earlier PostgreSQL versions than 9.1)
burnin: Enable multiple uploads

Extend Pithos burnin tests to enable multiple file uploading
of various sizes.
pithos: Fix metadata copying

Copy/move operations set/update the metadata
of the resulted object.
Metadata of other domains should be kept.
This commit restores this behavior broken
from a previous commit.
burnin: Test copy/move images
pithos: Enable stale snapshot better handling

Extend Pithos backend functionality in order to
be able to set the state of the snapshot.
This commit introduces the appropriate modifications
proposed in #231. More specifically:
* Changes 'available' flag (denoting the existence of the object mapfile
  in the backend) to integer.
* The 'available' field can be assigned with the following values:
  -1 (MAP_ERROR), 0 (MAP_UNAVAILABLE) and 1 (MAP_AVAILABLE)
* Provides a respective database migration script.
* Adds 'update_object_status' method in PithosBackend that is used in
  order to update the state of a Pithos object.
* Returns 400 (BAD REQUEST) response status when one tries to download a
  broken snapshot.
pithos: Test update object status functionality
docs: Document weblogin
pithos: Fix quota limit response

'X-Account-Policy-Quota' header should return the summary of all
the project limits.

Related issue: #250
docs: Document Storage API changes

Update Storage Service API and Changelog
to document changes regarding quotas.

Fixes #250