Some updates to get the code 'release ready'
- All the 'topology' altering methods now have a check to prevent their us after Geom/Phys/Phase objects have been created
- Removed stitch and join
- Cleaned up the check_data_health to print better warnings, while still returning the True/False flag
Merge branch 'develop' of https://github.com/PMEAL/OpenPNM into develop