Use FiniteStatePolicyEvaluator for alpha value computations.
Debugging lifted representation of beliefs in PBVI. Cleaning up code.

LiftedProperties are used to represent ground observed symbols in
beliefs and observations and actions in a policy. So running
a lifted policy is simplified (no need to track the policy's ground
history while running as each node in the policy should have the right
set of lifted properties). A bug to fix is getting the right next
policy (comparing observations correctly); right now, it is failing
to match many observations.

A lot of deprecated code and comments are removed and
The evaluation is now all done in FiniteStatePolicyEvaluator.
Some features are missing though like stopping early when hitting a
state with a known alpha value.