Update to 0.050

Upstream changes:
0.050		2016-05-06	T. R. Wyant
  Parse bracketed substitution with embedded comment. This is something
    like s{foo}\n#{bar}\n{baz} which is equivalent to s/foo/baz/. PPI
    gets this wrong, and we're not smart enough to fix up the PPI parse,
    but if given this as text, we now parse it correctly.

  We now recognize postfix dereferences by default, since Perl does
    beginning with 5.24. In other words, default new() argument
    'postderef' to true.

  Unterminated substitutions (i.e. 's//') should no longer cause an
    exception. Instead they parse as an unknown token.

0.049		2016-04-19	T. R. Wyant
  Robustify PPIx::Regexp->perl_version_removed()
    The problem here was that if the expression being parsed was
    sufficiently badly-formed, $self->delimiters() would be undef, throwing
    a warning.

  Correct dump of embedded modifiers (eg: (?i:...))


(wen)