Allow for Oblique Dipping Features

[danieldouglas92]

Finish what was started in #859. Below is a checklist for what is needed to finish this implementation.

• Allow oblique dipping features in Cartesian geometries

  • For slabs
  • For faults

• Allow oblique dipping features in spherical geometries

  • For slabs
  • For faults

[danieldouglas92]

Potential issues to check/protect against:

• If the obliquity vector aligns anti-parallel to the reference dip point?
• If the obliquity vector aligns parallel to the trench/fault trace?
• If the norm of the obliquity vector is 0?

I will update with more points if needed.