Revert "Merge pull request #472 from jimmyhchan/OPP"

Reverting Dust's prototypal lookup behavior. Dust will inspect Object prototypes to find properties.

This reverts commit dcc3d350214ab270bffe3a957f3b438b429651b4, reversing
changes made to ad2d39fd4f2e29223d27b94a19512f2bab45d05e.

Closes #479, #487.