Bug fixes and enhancements for mepo save

The mepo save command had some issues exposed in recent testing.

1. The command would save the new yaml file in pwd rather than at the "root" directory where the original was. This was a bit confusing, so the command now saves at root level
2. mepo save did not handle hashes well. There is no reason it couldn't save to a hash, but it labeled it as a branch in the yaml file which, while not broken, was in consistent.