Fixing blank line Flake8 failures
Add flake8 to Travis-CI to prevent these from coming back

Added new travis make target to skip flake8 on pypy but run it on all others
Removed duplicate flake8 since it has moved into requirements.txt
fix def / setv example
Merge pull request #282 from tuturto/doc

fix def / setv example
Merge branch 'master' into pr/280
Macro if-python2 for compile-time choice between Python 2 and Python 3 code branches
Add zero? predicate to check if an object is zero
Merge branch 'master' into pr/287