Field: Added FieldOps
- The only operation is to create a PetscFE
Field: Changed interface for specifying subfields
- Now addField() takes an order, and will create and layout the entire field
- Now updateDof() has been removed
- Now setupFields() uses PetscFE to do layout from the addField() information
- Added getField() to return the PetscFE for a given subfield, by name or number
- Removed the ability to do updateDof() over subparts of the mesh, like faces
- Fixed tests to use new addField()
- IMPORTANT: Now newSection() should really not be used. It will be removed in a future commit
Fault: Fixed splitDefault() to deal with new field specification
- This will fail for multiple fields, so more work is needed