Add unit tests for AssociationDict
Adds support for AssociationDict type for POST

The issue is that AssociationDict type does not have an `append` method
Add test for unique key (integrity) violation
Add rollback on integrity exception

Without the rollback any further writes to the database would fail.

issue #158
Return 404 on empty search result

An empty result should return a 404 not a 400
Fixes typo for association
Fixes newlines and quote type
Fixes superflous newline
Update basicusage.rst

Making the import statements and instantiation of objects consistent to the example found within the Quickstart guide.

Quickstart uses import flask.ext.restless instead of from import statement.
Updated the jQuery example to match the other ones

Updated the jQuery example to match the other ones search for instances of the model ``Person`` whose names contain the letter "y".
order by primary keys if no order_by is provided
catch DataError and ProgrammingError as well as IntegrityError, as all three can be caused by an API user
Sync comments with documentation to avoid confusion about pk restrictions
fix to ProcessingException message and status

bring it inline with docs
code instead of status_code and description instead of message
slight update to authentication doc example
fix typo in basicusage.rst
Merge pull request #294 from fly/fixtypo

fix typo in basicusage.rst
Merge pull request #292 from justinwp/patch-2

slight update to authentication doc example
Merge pull request #291 from justinwp/patch-1

fix to ProcessingException message and status