Raise self-formatted exceptions in SQlite.

 - A helper, marconi.tests.util.Expected, is added to replace
   testtools.ExpectedException, since the later one does not obey
   the exception hierarchy.

 - ClaimDoesNotExist is added, similar to MessageDoesNotExist.

Change-Id: I8f592184cbf7f3bdab95e9adef1306055097cb6f
Return (claim_id, message_iter) in SQLite create().

In general, POST should respond only the things not in users'
requests.  Similar to post() messages, which returns the msgids,
we return the created claim id, plus the claimed messages.

Change-Id: I61ad4a37f7cd5b2f42eece4fe4715db9ad878395
ClaimMessage Base Tests

Implements blueprint storage-base

Change-Id: I366a77596000d894fd8440c3afaa10ad8e0c6593
Bugfix: exclude expired messages in Queue stats.

Change-Id: I870ccab55cb2f39806026981fba241c66aa96218
Do not allow updating an expired claim in SQlite.

Change-Id: I6307959404602b998a87206815b53768e0d1931a
ClaimMessage implementation for mongodb

This is a first proposal os ClaimMessage support for the mongodb
storage. Please read comments in the code for a more detailed
explanation of this implementation.

Some issues and race conditions might be found and this implementation
tries to cover them in the best way.

More detailed review is required in the claim creation method

Implements blueprint storage-mongodb

Change-Id: I532fdad895a18dc4961a86adbe7086e9eaa231f9
Merge "ClaimMessage Base Tests"
Merge "ClaimMessage implementation for mongodb"
Claim support in WSGI.

Implements: blueprint transport-wsgi

Change-Id: I3ea265e275697c32288db0e36fdd1a893397e6ea
Check for malformed JSON when creating a queue.

Meanwhile,
    1. Dumps UTF-8 JSON in response;
    2. Set Content-Location for GET.

Implements: blueprint transport-wsgi

Change-Id: I04c988168366f60cf88a0693bab50ded5b855117
Delete queue in WSGI.

Change-Id: I4029e6f01763cb4bfdba3a4e9c6eacf972173923
Implements: blueprint transport-wsgi
List queues in WSGI (w/o paging, but compatible).

Change-Id: I1e56317b762dc079dbb00751400817c049e927db
Implements: blueprint transport-wsgi
Queue Stats in WSGI.

Change-Id: Ic3652dd1c7e7a97323c9c7d86b281c4f1691532d
Implements: blueprint transport-wsgi
Make use of the features in falcon 0.1.3 & 0.1.4

 * To build the query strings;
 * to build content_location;
 * and to ensure the type of the HTTP parameters.

Implements: blueprint transport-wsgi

Change-Id: Ibc06d68e43313e842854f08a8bff010624e7516c