ometa.runtime.ParseError.formatError can't deal with InputStreams

[Aaron Gallagher]

The line ``lines = str(self.input).split('\n')`` will stringify an InputStream into something like ``<ometa.runtime.InputStream object at 0x10134c850>``.

    >>> g = BootOMetaGrammar("""
    ... foo = 'a':one baz:two 'd'+ 'e' -> (one, two)
    ... baz = 'b' | 'c'
    ... """, {})
    >>> gg = g.parseGrammar('g')
    >>> i = TrampolinedGrammarInterpreter(gg, 'foo', callback=print)
    >>> i.receive('foobar')
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/Users/habnabit/.local/lib/python2.7/site-packages/ometa/interp.py", line 43, in receive
        for x in self.next:
      File "/Users/habnabit/.local/lib/python2.7/site-packages/ometa/interp.py", line 158, in apply
        for x in self._apply(f, ruleName, argvals):
      File "/Users/habnabit/.local/lib/python2.7/site-packages/ometa/interp.py", line 96, in _apply
        for x in rule():
      File "/Users/habnabit/.local/lib/python2.7/site-packages/ometa/interp.py", line 190, in parse_And
        for x in self._eval(subexpr):
      File "/Users/habnabit/.local/lib/python2.7/site-packages/ometa/interp.py", line 215, in parse_Or
        raise ParseError(self.input, *joinErrors(errors))
    ometa.runtime.ParseError:
    <ometa.runtime.InputStream object at 0x10134c850>
    ^
    Parse error at line 2, column 0: expected the object 'a'

[Allen Short (washort)]

See http://bazaar.launchpad.net/~washort/parsley/trunk/revision/136