Don't create a Panel for a seperate render window.

Instead of setting RenderParent to null and raising complexity RenderFrame can be its own parent.
Remove CPanel.

Let the RenderFrame handle those messages.
Remove wxTAB_TRAVERSAL style from RenderFrame.
Fix RendererHasFocus().
Prevent DXGI from making changes to the window.

Prevents DXGI from responding to Alt+Enter and messing up our fullscreen handling.
D3D: Request desktop resolution before overriding the buffer size.

This fixes issues where the wrong refresh rate is selected for some monitors.
D3D: Make the swapchain available outside of the namespace.

This commit reverts a part of pull request #579.
D3D: Add exclusive fullscreen support.
D3D: Return to windowed mode before destroying the swapchain.
D3D: Initialize the renderer in exclusive fullscreen mode if it is enabled.
Remove fullscreen flag from video config, detect it from RendererIsFullscreen() instead.
Renderer: Restore windowed size after exiting fullscreen.
Renderer: Restore exclusive mode after focus has been regained.
Exit fullscreen when user is prompted to confirm stop.

And fix a small typo while we're are it.
Cosmetic changes based on feedback on PR #506.
D3D: Don't set the windowed mode size when we initialize in fullscreen.
Render: Adjust rectangle before restoring the window size.
Renderer: Don't attempt to switch to exclusive fullscreen if "render to main" is enabled.
VideoConfig: Replace "3D Vision" by "Exclusive Fullscreen" option.

Also remove the 3D Vision hack that should no longer be necessary.