flake8 requirements: Update pyparsing to 2.1.5

- Added ParserElement.split() generator method, similar to re.split().
  Includes optional arguments maxsplit (to limit the number of splits),
  and includeSeparators (to include the separating matched text in the
  returned output, default=False).

- Added a new parse action construction helper tokenMap, which will
  apply a function and optional arguments to each element in a
  ParseResults. So this parse action:

      def lowercase_all(tokens):
          return [str(t).lower() for t in tokens]
      OneOrMore(Word(alphas)).setParseAction(lowercase_all)

  can now be written:

      OneOrMore(Word(alphas)).setParseAction(tokenMap(str.lower))

  Also simplifies writing conversion parse actions like:

      integer = Word(nums).setParseAction(lambda t: int(t[0]))

  to just:

      integer = Word(nums).setParseAction(tokenMap(int))

  If additional arguments are necessary, they can be included in the
  call to tokenMap, as in:

      hex_integer = Word(hexnums).setParseAction(tokenMap(int, 16))

- Added more expressions to pyparsing_common:
  . IPv4 and IPv6 addresses (including long, short, and mixed forms
    of IPv6)
  . MAC address
  . ISO8601 date and date time strings (with named fields for year, month, etc.)
  . UUID (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
  . hex integer (returned as int)
  . fraction (integer '/' integer, returned as float)
  . mixed integer (integer '-' fraction, or just fraction, returned as float)
  . stripHTMLTags (parse action to remove tags from HTML source)
  . parse action helpers convertToDate and convertToDatetime to do custom parse
    time conversions of parsed ISO8601 strings

- runTests now returns a two-tuple: success if all tests succeed,
  and an output list of each test and its output lines.

- Added failureTests argument (default=False) to runTests, so that
  tests can be run that are expected failures, and runTests' success
  value will return True only if all tests *fail* as expected. Also,
  parseAll now defaults to True.

- New example numerics.py, shows samples of parsing integer and real
  numbers using locale-dependent formats:

    4.294.967.295,000
    4 294 967 295,000
    4,294,967,295.000

misc/requirements/requirements-flake8.txt

@@ -23,7 +23,7 @@ pep8==1.7.0
 pep8-naming==0.3.3
 pydocstyle==1.0.0
 pyflakes==1.2.3
-pyparsing==2.1.4
+pyparsing==2.1.5
 six==1.10.0
 sortedcontainers==1.5.3
 venusian==1.0