Added partial checking for encoding job status

- New code for checking status of an encoding job at zencoder.
- This code is incomplete, and still does not treat error cases,
     nor does it wait any period for the job's completion.
- Error class added, but is incomplete.
Fixed error page call for request errors

Now when there is an error on the zencoder job request,
it will call an error page to let the user know.
Removed request creation to external functions

The creation of job and status requests for zencode
is now on separate functions to reduce code clutter.