Full Offline Functionality

In this release, tApps can now work fully offline through a pre-made service worker. Using tApp.install() automatically registers the premade service worker, but a service worker URL can be passed through the method. tApp.update() will attempt to update the service worker, and tApp.uninstall() will attempt to remove the service worker. For offline POST requests, a developer can modify the commented lines in the service worker and insert edge cases for if a POST request fails (by default, normal POST behavior is executed). There are also some improvements to the caching system.