- removed a few unnecessary temporary objects
- unnecessary copy-construction of objects
- formatting cleanup (whitespaces)

This increases the readability of extract_texture a lot.

- Added an assert that checks for texcoords
- Pulled over changes from affine renderer - adding const and static_casts instead of C-style casts

- Taking a 3x4 affine matrix and adding an orthogonal row to make it 4x4
- Removed all transformations from clip to screen space as our camera matrix now goes directly from world to screen space
- Removed division by w (it's 1 anyway)

- It works with our affine camera matrices estimated from the H&Z algorithm
- Performs depth testing and rasterises triangles
- Vertex-colouring only, no texturing
- Will be used for the texture extraction

The assembly on VC14 is the same, but anyway!

Added cereal include directory to CMake

In preparation for the serialisation - and declared it empty, to work around a VS bug with =default

Fixed PcaModel c'tor, forgot to copy the arguments

Expects an isomap to exist with the filename <imagename>.isomap.png.