Description of proposed changes

Here a few updates for prep_fringe.

• you can specify the input argument --geom-only to only write out geometry files (useful for making masks)
• you can specify looks (this is only for tracking metadata)
• if it can find connected component files, it will make ifgramStack.h5.
  • it will find them as long as they're the same names as the unwrapped interograms (required input) except with .conncomp extension

Reminders

• Pass Codacy code review (green)
• Pass Circle CI test (green)
• Make sure that your code follows our style. Use the other functions/files as a basis.
• If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.
• If adding new functionality, add a detailed description to the documentation and/or an example.