specification of control point (vertex) type

defined YAML and affect the UI response

Definition:

1. Fiducial/ Feature = must be defined by a user; always exist in the image; easily identifiable by image pixel, gradient, corner, etc., e.g., ear tips, both ends of an eye.=
2. Interpolated = coordinates is interpolated as a ratio (specified in YAML) between 2 points along a line segment, e.g., points on eyebrow
3. convex = convex hull combination of more than 2 vertices, forming a polygon, e.g., cheek

UI Effect:
When the user move point no 1. points 2 and 3 will be calculated and followed accordingly