Correct typo in documentation
Make upload destination an optional argument

Fixes #11

In "kamaki file upload", the destination path is now an optional
argument, set to be equal to the base name of the source path, by
default.
Separate empty dir, empty container, etc. errors

This fix affects "kamaki file list [/CONTAINER[/PATH]]" command

Before this fix, if there were no results to show to the user, an
"empty container" notification would appear.
Now, the command distinguishes between the various cases:
 - empty container
 - empty directory
 - non-existing object
 - non-directory object
and notifies appropriately.
Initialize OS block storage REST API clients

Package name: kamaki.clients.blockstorage
Add unit tests for Block Storage REST client
Implement Block Storage client
Add unit tests for Block Storage client
Implement Cyclades Block Storage rest client

Includes unit tests
Implement Cyclades Block Storage client

The Cyclades client overrides some methods of the OS-specific
client, due to API differences: create_volume, create_snapshot

Unit tests for these methods are also implemented
Expose volume & snapshot commands (Block Storage)