Some changes. Commiting to change branches.
Refactored matrix contract code some. Commented out tests that expect MiniTest Assertions but throw something else currently.
Removed exception print from coercion check. Moved generic postcondition failure to contract module.
Changed based on review
Merge pull request #19 from isupeene/bsotaer-refactoring

Bsotaer refactoring. Merge #19.