ParserGenApp throws an exception on MiniMath grammar

[jbrennan]

Trying to generate a parser for the MiniMath grammar from your tutorial, it throws an exception when trying to generate for the provided grammar. I also tried rolling back to the previous commit (the same one which is pointed to by the MiniMath repo submodule pointer) and got the same result.

I also made sure to make the ParserGenApp options match what was shown in the tutorial.

When directly cloning the MiniMath project (and its parsekit submodule), it works as expected.