Added downloads badge
Testing resources
Added `shiva.utils.parse_bool` helper

It parses the string 'false', '0' and '' as false values. Any other value is
evaluated as true.
Testing tracks
Merge pull request #129 from tooxie/tests

MOAR TESTS!
Added relationship tables

Relationships are many to many between track <> artist, and track <> album.
This means that there is no artist <> album relationship any more. There is,
however, a calculated attribute `Artist.albums` and `Album.artists`.
Tests for PUT method

It could use some more corner cases, but it's good enough for a start.
PUT method

We add the possibility to update our models using the PUT method.
Running tests wiped out the main DB

Fixed bug which wiped out the main DB after running the tests.
Merge pull request #128 from tooxie/put

PUT method
Enforcing a SECRET_KEY

The SECRET_KEY config will be used for signing the authentication token. Shiva
refuses to start if this setting is not defined.
Merge pull request #131 from tooxie/SECRET_KEY

Enforcing a SECRET_KEY
Abstracting away repeated logic
Dropped request.values usage

The dictionary `request.values` contains both querystring arguments and
POST/PUT body arguments. It's better to be explicit about where those values
should be coming from.
Merge pull request #132 from tooxie/dry

DRY
Smarter response

The `shiva.http.JSONResponse` object does some checks in case of error. The
function `flask.ext.restful.utils.unpack` was extended.
Merge pull request #134 from tooxie/unpack

Smarter `shiva.http.JSONResponse`
Improved shiva.utils.parse_bool
Merge pull request #133 from tooxie/parsebool

Improved `shiva.utils.parse_bool`
Query string parameters