Added system.wait for promise-based timeouts.
A minor improvement to serializer space settings.
Added plugin load failure errors.
Removed old skeletons folder from src.
Updated changes doc.
Fixed some typos in the changes doc.
WIP on observable module.

-Comparing my original implementation with Steve's.
-Adding some missing APIs
-Improving the existing API
-Work left to do on arrays.
Additional work on observable arrays.

Still not tested yet...