Adding the URDMESolver class
URDMESolver classes now work for the NSM solver and examples
Bug fixes on URDMESolver interface
One more bug fix for URDMESolvers
No longer uses the local .urdme directory
Major changes so that we can pickle/unpickle the solver object, for using with remote/cluster computation
Merge pull request #19 from briandrawert/refactor

Refactoring the Solver execution model