[Contracts] Allow contracts statuses to carry information
e.g., failing contracts can carry a counter-example, successful contracts can carry a proof
(from redmine: issue id 2357, created on 2015-06-11, closed on 2015-06-13)
e.g., failing contracts can carry a counter-example, successful contracts can carry a proof
(from redmine: issue id 2357, created on 2015-06-11, closed on 2015-06-13)