dxwin - beginnings of a simple single header d3d11 renderer

A lot of my previous code has been dx9 based.  Going forward, i want the ability to quickly whip up dx11 based samples so i can integrate these with modern systems (including fancy display devices) that interface better via dx11.

when i used to be working at intel there wan't much much reason to use the more modern graphics apis when the hw features it enabled weren't all available on the company's graphics.  Also, I had been focusing on other areas of simulation and vision and thus didn't have too much time to spend on graphics.  Furthermore, I've never had much of a need to be building a high fidelity engine that supported a lot of content.  For this work, i just need some adaquate rendering techniques (such as shadows and some decent shading such as parallax) for good visualization, prototyping concepts, and tech-centric demos.

This git commit represents a day (saturday) and a bit (friday evening) of me getting familiar with dx11-isms, starting to organize things to maintain the needed flexibility while hardcoding away stuff that i wont care about, and trying to simplifying down to keep it small.  For example, I can keep things simple if I always just use the same vertex buffer format, even if some shaders dont need vertex color, for example, the little bit of extra space isn't going to matter for the types of samples i'll likely build with this.

BTW the vertex buffer format uses a quaternion for tangent space basis.
it converts to tangent-binormal-normal (matrix) in the vertex shader to avoid any interpolation issues due to quaternion double coverage.

Have yet to update the dx9 pixel shader set and include them here.  as well as a handful of additional 'todo' items.

Yeah, if you run the exe right now, its just a spinning triangle at this point.  But unlike opengl, the developer has to build a lot from scratch.