Update projectM visualizer to latest 4.1 release

[kblaschke]

The built-in projectM visualizer is quite old (2.2.x as fasr as I can see from the build files).

projectM should be updated to the latest stable release (4.1.1 or later), as with version 4.1, the visualizer has become almost fully compatible to Milkdrop 2.0 and gained some stability, performance and API improvements since the previous releases.

The new API is C-based to the currently used C wrapper is no longer necessary - the functions can directly be used from Pascal. Additionally, projectM now also properly builds as a DLL on Windows. All functionality is now available via the API, no more key handler or config struct with unused fonts.

The next release will also feature additional API calls like being able to render to a custom framebuffer instead of the native surface, plus other things. Since 4.0, the API remains forward-compatible within a major release, and minor releases will only add new API functions, but never change or remove existing ones, making updating projectM a non-effort, not even relinking is required.

[s09bQ5]

I already tried to update projectM once. It didn't work. There where graphics issues IIRC.
USDX uses an OpenGL 1.x/2.x context. projectM beyond 2.x needs OpenGL >= 3. We don't create a separate OpenGL context for projectM but instead try to save and restore the context state before and after calling the renderFrame method.

[kblaschke]

That makes sense, sure. Not sure how much work it would be to use an OpenGL 3.3 context for the whole application, but I guess that is more involved as converting the fixed-function pipeline to shaders etc.