Lambdascope by Semantic Readback

Proof-of-concept code for an optimal implementation of the lambda-calculus per the semantic readback (using context semantics) in the paper Lambdascope. The concept proven is that the implementation is (experimentally) optimal (same number of family steps as BOHM). The default example in Main.java is c2 (c2 c2) (for c2 the Church numeral 2) which evaluates to c16 (the Church numeral of 16), as expected.