Stop silencing useful information.
Stop silencing useful information.

The thrown errors didn't hold any useful information and made debugging
impossible.

Before:

    Error: Could not parse jison grammar

After:

    Error: Parse error on line 86:
    ...   ;expatom    = atom '^' nat
    --------------------^
    Expecting ':', got 'ID'

GerHobbelt/jison,GerHobbelt/jison,GerHobbelt/jison,GerHobbelt/jison