- extended TriangleToRasterize
- process_prospective_tri()
- added plane class
- added clip_polygon_to_plane_in_4d()

Moved affine-specific rendering to render_affine_detail.hpp, added raster_triangle() for the generic case

Set version to 0.

To facilitate this, added a get_texture_coordinates() method to MorphableModel

Clarified installation instructions for the header include paths

The OpenGL mathematics library (http://glm.g-truc.net/) - it'll be used for its 3D rendering related functions

Also updated the documentation of Mesh.

Additionally: Using '//' for the forward declarations so they don't get picked up by doxygen

This makes all free functions show up in the generated documentation.

- We now use the same values and formulas as in Smith & Aldrian for the detector 2D variance.
- This changes the ranges of values a bit, so set an equivalent reasonable regularisation default value

Changed the detector variance in the shape fitting from clip-coords to image-coords. This makes the regularisation behave normal again.

Also chose a slightly higher regularisation value to stay a bit closer to the mean face by default.