Switch vecmath to f32.
vec3_dot should be a * b, not a * a.
camera: compute the view matrix correctly, and remove dead vecmath code.
camera: provide a method to compute a projection matrix.
Move rendering to hgl. This adds a dependency on rust-image and removes those on rust-graphics and opengl_graphics.
Merge pull request #49 from eddyb/hgl

Migrate to hgl for rendering.