Fixes optional dependency injection problems

Problems were occurring in live environments when attempting to inject optional dependencies for use with session storage features. This commit provides the following optional dependency injection mechanism:
* Get the dependency provider using the app injector instance
* Create an isolated injector instance with ng, ng* and kinvey modules available
* Pass the dependency provider factory $get method to the isolated injector’s instantiate method
* Link the rootscope associated with the isolated injector with the app rootscope

This fix has been verified in live environments, but there are no tests to support it.