Issue #26  Add test for shadow caching.

Hi Bryce,
Changes are verified and tested. Some points.
1. Output for EGL backend is too slow. If we reduce the context size to 10 or 5 it was better.
2. I am facing issue with Maskfilter in my PC. Issue #99 has been raised for the same. Can you please verify if its fine in your environment. 

Thanks,
Suyambu