More document redaction.
Completed statement evaluation documentation.
Cleaned up implementation a bit.
Renamed 'field(t, k)' expression to access(r, k) for more clarity. Also renamed 'concatenate' operator to 'cat'.
Updated syntax to match documentation.
Implemented a few helper predicates.
Modified 'run.sh' to allow passing arguments to the Lua program.
Changed the way chunks are evaluated, and added command line arguments.
Added syntax for type operator.
Implemented the semantics for all terms except unary and binary operators. lua2prolog works but needs to be updated; this will be done when implementation of Prolua's semantics is complete.