Rule-X: A multi-constraint policy solver

Rule-X mainly focuses on a multi-constraint solver with an open programming interface to describe various problem domains. A declarative policy language is used and driven by the solver. The solver get models and constraints defined by the language interface and from other side get data which claim to be belong to the models, the solver output data which meet all the constraints. The solver mechanism works like SAT solver (which handle first order logic) but has difference, due to it is more policy oriented which can handle mix of logical and extreme problem. It is problem domain neutral so can support multiple plugins for versatile policy scenarios.