first 10 % of #2124
- added initial version of JSON API tests
- renamed error.errorCode to error.code
- renamed tags.all to tags.browse for consistency
- changed cookieSession to session
- added session.regenerate for login and logout
- added bookshelf session store
- added session table to database
- added import for databaseVersion 001
- added grunt task test-api
- cleanup of gruntfile to start express when needed only
- moved api tests to functional tests
closes#1396
- moved core/test/unit/api* to core/test/integration/api/
- moved core/test/integration/model* to core/test/integration/model/
- moved core/test/unit/utils to core/test/utils
- moved core/test/unit/fixtures to core/test/utils/fixtures/
- changed gruntfile.js to execute api tests with target 'integration'
