Add a constructor to override database setting

The database was hardcoded to always follow Django settings. Now it
is a bit more dynamic.
Merge pull request #8 from tunix/feature/pep8

Feature/pep8
Merge pull request #3 from ferrix/client

Add a constructor to override database setting
Merge branch 'master' of git://github.com/tunix/tastypie-mongodb-resource into tunix-master

Conflicts:
	tastypie_mongodb/resources.py
Merge pull request #10 from tunix/master

if object not found raise ObjectDoesNotExist so that tastypie returns 404
Merge pull request #11 from tunix/master

fixed non-working schema
Simple filtering feature added
added authorization methods to all obj* methods + added filtering to obj_get_list