Parser shaping up
bug fix : menhir priority level was inverted earlier, fixed
Incremental improvement
Added NetKAT lexer and parser to build stage, though they are not building as of now
adding lexer for NetKAT
grammar broken into different fields of headers and the type of values that they expect. Build errors related to types have not been resolved
Parser Compiling successfully
Few comments modified
Support code for quick testing

- repl added via frenetic/netkat_test.ml for quick testing, supposed to go away with time
- support structure added for building netkat_test, again supposed to go away with time