version 2 JSON/XML web api

- created new controller webapiv2
- JSON/XML web api accessible via api/[object]/[endpoint].[json|xml]
where object is assignments, categories, devices, products, results,
stencils, tags, test_cases, test_plans, users, or versions and endpoint
varies depending on object but most contain at least search and create
- invalid routes or endpoints are caught and return an error message
- authentication is provided via an auth token associated with a
privileged web api user like the v1 api
- implemented a fix for the v2 api so that a user session does not need
to be established for api access, only the correct auth token is
necessary
- api follows the style of the reedit and twitter apis which seem to be
using ruby on rails as well
- backwards compatibility with existing xml api is maintained as the
previous route and controller remain untouched
- updated gem file dependencies
- created RSpec unit tests for all api calls which are run with the
command “bundle exec rspec” from the root testcasedb directory