JCLOUDS-342: Retry on HTTP 408 for swift

To repro issue 342, the following steps were taken:
 - Spawn 500 parallel / 2000 total putBlobs to cloudfiles-uk
 - issue a SIGSTOP
 - wait 60 seconds
 - issue a SIGCONT

Without this patch, there are several hundred 408s.
With this patch, these are retried and complete successfully.
JCLOUDS-460: Add jitter to avoid thundering herd

When issuing many simultaneous requests to Synaptic Atmos I observed:

HTTP/1.1 failed with code 500, error: AtmosError
[code=1040, message=The server is busy. Please try again.]

Previously all clients slept for fixed intervals and thus retried
around the same time.  This commit adds a random delay which should
better distribute load on the provider.
Address Checkstyle violation
JCLOUDS-486 This will allow booting up nova servers with fixed IPs and ports.
Fixing a couple of typos
Updating the features section to match the website
Address Checkstyle violations
JCLOUDS-453. Add OpenStack Keystone v2.0 OS-KSADM Admin Extension support for Keystone.
JCLOUDS-489 - Adds support to Cloud Files for the iOS Streaming URI
Retry on S3 HTTP 504 Gateway Timeout status codes

RiakCS using the S3 interface occasionally surfaces these status
codes.
Fix Keystone response for testing to not include Glance version
Fixes potentially deleting a null server id.
Remove Nova instance metadata limit

Rackspace cloud limits instance metadata to 5 key-value pairs, but
upstream Nova only sets the limit at 128 by default.  This patch removes
the limit entirely; the official python clients don't check it and the
server is responsible for enforcing it anyway.

Fixes:  https://issues.apache.org/jira/browse/JCLOUDS-507
JCLOUDS-510 Delete objects in a container efficiently.

The existing approach for deleting objects in a container suffers
from a head-of-line blocking problem. This commit implements a better
scheme which does not have that problem. This scheme uses a counting
semaphore for making sure that a certain number of futures are
issued in parallel. As each of these futures is completed, one
permit of the semaphore is released.

Added unit tests for testing this new scheme.
JCLOUDS-516: Add ssh agent support via sch agentproxy
JCLOUDS-347: Implement a poor-mans rollback if CloudStack static NAT creation fails
JCLOUDS-515: Don't require availability zone when creating volumes in cinder
Supporting uppercase user names in Azure blob live tests
Add deprecation warnings and provide links to new APIs
JCLOUDS-317: Add missing states to Nova v2 Server

- Deprecated state: STOPPED
- Add states:   MIGRATING, SHUTOFF, RESCUE, SOFT_DELETED,
                SHELVED, SHELVED_OFFLOADED