Wrong shapre of uv_vertices

[Robin970822]

https://github.com/YadiraF/face3d/blob/2fc26906d159a11398cd3e7a9b3f16b6f8937da3/examples/Data/BFM/show.m#L36

uv_vertices should be in a shape of 2x53216 instead of 53216x2. Thus, the code should be

uv_vertices = [uv_coords; zeros(1, size(uv_coords, 2))]'