Updating device models

- grunt: path check for saas and convert
- grunt: npm and bower check for dependencies
- backbone: added methods to the location, os and device models
- backbone: made location and os models initially instanciated
- test: testing device collection and model methods
- test: adding chai and sinon
- test: changing chai from should to expect
- package.json: changing npm test methods to use relative paths
- server.js: adding fields for checkout and checkin