The existing TriangleMesh API is specified to support one and only one particular vertex format. We will need to make at least 2 changes to allow TriangleMesh be used for a range of vertex format in the future:

1) faces the ObservableIntegerArray has to make into a class (may name FaceArray) that extends ObservableIntegerArray. It should have methods (in the future) to provide view to the components in the faces.

2) The following constants need to turn into methods in appropriate classes:
    public static final int NUM_COMPONENTS_PER_POINT = 3;
    public static final int NUM_COMPONENTS_PER_TEXCOORD = 2;
    public static final int NUM_COMPONENTS_PER_FACE = 6;