gui_toolkit 0.11.0

Changed

• Shaders compiled ahead of time: render/rect.hlsl and render/filter.hlsl are embedded as DXBC
  (render/shaders/*.dxbc, render.SHADERS) instead of being compiled by D3DCompile when the renderer starts
  (280 ms to 1.5 s of every launch, rect.hlsl's pixel shader dominating). odin run tools/shaders writes the blobs
  after an edit of the HLSL; tests/shaders fails while one is stale. -define:RENDER_COMPILE_SHADERS=true compiles
  at start-up as before. render.shader_compile(id).
• Resizing without ResizeBuffers at every step: render.resize keeps the swap chain's buffers larger than the
  window (rounded up to set_resize_slack pixels, default DEFAULT_RESIZE_SLACK = 256) and only changes the presented
  region (IDXGISwapChain2::SetSourceSize, microseconds) while the window fits in them; they are reallocated once per
  slack crossed, and made smaller when they hold more than twice the pixels shown. ResizeBuffers cost 1.6 to 3.5 ms
  a step. render.buffer_size. The window's swap chain is created with DXGI_SCALING_STRETCH (with NONE, DWM showed
  a smaller source region magnified).