fixed function errors in grammar

extra ENDST after block in funcdecl, resulting in wrong parse of functions without GTFO, but with FOUND YR
also moved fragment LETTER to the right place
who knew you have to specify -visitor -no-listener parameters in antlr command line, i spend shitload of time trying to make it work
function arity and grammar ambiguity

function calls requare MKAY in the and, and call paramaters are listed as YR <par> N YR <par> .....
close issue #10 and #8

- add dummy statement rule which holds any expression
- add TreeDummyStmt node
- function call is now an expression
- for more info see issue #10 comments