fixing little things
add snippet that exposes bad error message
fix operator tokens so that each character is recognized as an individual token; and comments about how to use white space to differentiate pre-, post, and binary operators
Update ObjC grammar to 2014 standards
Merge pull request #79 from Cmejia/master

Update ObjC grammar to 2014 standards
added plm gam mar
fixes to bnf.g4
updates to bnf grammar
added pl/m example
Merge pull request #81 from teverett/master

Updates to BNF
recompile of bnf
Merge branch 'master' of https://github.com/antlr/grammars-v4 into bnf2antlr