Bump minimum pyparsing version to 2.0.1, replace deprecated << with <<= and remove no longer relevant work around.
Monkey patch pyparsing so that we can support pyparsing >= 1.5.6 on both Python 2 and 3 without loads of deprecation warnings.
Install latest version of pyparsing
Exclude use of pyparsing 2.0.0 everywhere
Merge pull request #1 from mdboom/pyparsing-monkey-patch

Pyparsing monkey patch
Merge pull request #2279 from jenshnielsen/pyparsing

Pyparsing