Add a utility class to hold checker results.

Add a simple class to hold the results of a failed query to a SMT checker.
Also, it has a utility function to easily generate a matlab expression for
the failed test's counter-model.  Also test.

git-svn-id: https://groke.mcmaster.ca/svn/grad/colin/branches/TableTool_javization@10662 57e6efec-57d4-0310-aeb1-a6c144bb1a8b