Merge branch 'dev'

Fix error when git not installed on user machine

moving import of git inside try/except

Merge branch 'dev'

Merge branch 'dev'

Merge branch 'dev'

updating version number

fixing merge mess all tests pass locally

Bumping version number to 1.7.0

Increasing version number for deployment to PyPI

Merge pull request PMEAL#682 from PMEAL/deploy_to_pip

adding version number to openpnm, setting up autodeploy to pip