Most of it was done by Andrew Eikum.

While at it, use D3D-like uniforms for the light parameters and
(consequently) implement range and proper D3D spotlights support.

It's only an implementation detail that the direction needs to be passed
to the fixed function GL pipeline as GL_POSITION.

It's a direction so we don't want to get translations applied to it.
The variable is only used internally.

Some applications don't forward WM_SIZE to the window proc.

The dates were changed some time ago. DST starts now on the second
Sunday in March and ends on the first Sunday in November.