FEATURE addFullRequestInterceptor() now accepts callback returning promises

AddFullRequestInterceptor now supports callbacks, that return promise. 
Side effect feature - if a promise from requestinterceptor is rejected, the whole request is rejected.

My use scenario is, that I check user logged in status in interceptor and if user is not loged in, I show a modal login form. My login form returns promise. So when a user logs in, the original request continues...

It's a bit quick and dirty and probably needs some additional testing.