Add README file
Add LICENSE
Wff: Change 'parse :: String -> Wff' to 'parse :: String -> Maybe Wff' in order to add error checking
Wff: Refactor multiple applications of print to a single application of mapM_
Wff: Modify main to print test string along with result of parsing
Wff: Create Wff module and move 'main' to TestTheorem.hs
isAxiom: Set up test framework for 'isAxiom :: Wff -> Bool'
isAxiom: Implement 'isAxiom :: Wff -> Bool'
Wff: Export all value constructors for the Wff data type
TestTheorem: Refactor tests to use HUnit
parse: Use applicative style to simplify error checking
TestTheorem: Add labels to individual Tests