ENH: AMI improvements

- Added new faceAreaWeightAMI2D AMIMethod:
  - performs intersection using a new 2D triangle class;
  - candidate face matches set using an AABBTree method (vs advancing front for
    faceAreaWeightAMI).

  - Use by setting the AMIMethod entry when specifying the AMI in the
    constant/polyMesh/boundary file, e.g.

        AMI
        {
            type            cyclicACMI;
            AMIMethod       faceAreaWeightAMI2D; // new method
            Cbb             0.1; // optional coefficient
            nFaces          1000;
            startFace       100000;
            matchTolerance  0.0001;
            transform       noOrdering;
            neighbourPatch  AMI1;
            nonOverlapPatch AMI1_non_overlap;
        }

  - The optional Cbb coeffcient controls the size of the bounding box used when
    looking for candidate pairs; the value of 0.1 is the default and worked well
    for a large range of test cases. For badly matched AMI patches this may need
    to be increased.

- Deprecated the partialFaceAreaWeightAMI class - primarily used by ACMI:
  - functionality now offered by the AMI variants.