Merge pull request #25 from escherba/pf_interface_refactor

only perform setup clean when virtualenv is present
Merge pull request #26 from escherba/pf_interface_refactor

add exec.sh as package_data
Merge pull request #27 from escherba/pf_interface_refactor

use package name in package_data
try a glob instead
remove unused lines
prettier output, better variable names
Merge pull request #28 from escherba/master

use a glob to include exec.sh, also some refactoring