RFE: Support of Ligature Caret List

Submitted by Behnam Esfahbod

Description

http://www.microsoft.com/typography/Glyph%20Processing/detail.mspx: """ The Ligature Caret List defines the positions for the caret to occupy in ligatures. This information, which can be fine tuned for particular bitmap sizes, makes it possible for the caret to step across the component characters of a ligature, and for the user to select text, including parts of ligatures."""

"""The Ligature Caret List can contain positioning data in both X and Y directions."""