removed binding.pry
changed recreate_object_graph to work with fields of higher arity;
polished the Bridge API
added some push-button methods
added some comments
renamed some methods
moved the file_system model into a separate file
moved the address_book model into a separate file
fixed formatting in imports.rb
changed the execute_command to accept either command index or command name
added the 'satisfiable?' method to solution.rb
changed syntax for commands to allow for command names and commands without a body
changed alloy_printer to print out commands without a body differently
updated address_book and file_system tests to check for unsatisfiable commands
merged with ido