don't install empty dirs during wheel installs
a teardown that pytest recognizes
Use the deadsnakes PPA for a not so dead snake (3.4).
Yes yes yes.
move directory creation below the file filtering
use copy2, not move, to ensure dirs are not copied
Merge pull request #1743 from qwcode/empty_dirs

don't install empty dirs during wheel installs
merge 1.5.X to empty_dirs_develop
pep8 fixes
Merge pull request #1760 from qwcode/empty_dirs_develop

port #1743 to develop