Upgrade Raylib to 6.0 (#337)

* Updated target to Raylib 6 + synced invoke called with the changes in C. [WARNING: Breaking changes!]

* Added severial examples. Corrected towards the correct return type and add utilities to prevent working with pointers

* Additional resources from the Raylib repo.

* Fixed additional pinvokes to match with the new raylib bindings. [Warning breaking changes!]

* Fixing the QOL utils

* Fixing the Mesh struct

* Applying changes after review. Merged resources.LICENSE + raylib-cs.Native.csproj only targets dotnet8

* Updated README to reflect .NET 10 and Raylib 6 compatibility changes.

* Updated shader colors, adjusted car model scale, disabled HDR in SkyboxDemo, and fixed camera mode assignment. Removed unused `Capacity` field in FilePathList struct.

* Improved XML comments for consistency, fixed spacing and formatting across examples, added new resources to `resources.LICENSE`.

* Updated XML comment for `GetDirectoryFileCountEx` to clarify behavior and filtering options.

* Updated and clarified XML comments for methods and parameters, improved naming consistency, and refined shader-related functions. Renamed enums in `Shader.cs` for so it is inline with the upstream.

* Improved XML comments for clarity and consistency in `Model.cs` and `Mesh.cs`, updated method and variable names for better readability, and adjusted logic in span creation methods.

* Corrected XML comment capitalization in `Model.cs`.

---------

Co-authored-by: Meatcorps <info@meatcorps.nl>

Examples/resources/shaders/glsl120/julia_set.fs

@@ -0,0 +1,80 @@
+#version 120
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+uniform vec2 c;                 // c.x = real, c.y = imaginary component. Equation done is z^2 + c
+uniform vec2 offset;            // Offset of the scale.
+uniform float zoom;             // Zoom of the scale.
+
+// NOTE: Maximum number of shader for-loop iterations depend on GPU,
+// for example, on RasperryPi for this examply only supports up to 60
+const int maxIterations = 255;  // Max iterations to do
+const float colorCycles = 1.0;  // Number of times the color palette repeats
+
+// Square a complex number
+vec2 ComplexSquare(vec2 z)
+{
+    return vec2(z.x*z.x - z.y*z.y, z.x*z.y*2.0);
+}
+
+// Convert Hue Saturation Value (HSV) color into RGB
+vec3 Hsv2rgb(vec3 c)
+{
+    vec4 K = vec4(1.0, 2.0/3.0, 1.0/3.0, 3.0);
+    vec3 p = abs(fract(c.xxx + K.xyz)*6.0 - K.www);
+    return c.z*mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
+}
+
+void main()
+{
+    /**********************************************************************************************
+      Julia sets use a function z^2 + c, where c is a constant
+      This function is iterated until the nature of the point is determined
+
+      If the magnitude of the number becomes greater than 2, then from that point onward
+      the number will get bigger and bigger, and will never get smaller (tends towards infinity)
+      2^2 = 4, 4^2 = 8 and so on
+      So at 2 we stop iterating
+
+      If the number is below 2, we keep iterating
+      But when do we stop iterating if the number is always below 2 (it converges)?
+      That is what maxIterations is for
+      Then we can divide the iterations by the maxIterations value to get a normalized value
+      that we can then map to a color
+
+      We use dot product (z.x*z.x + z.y*z.y) to determine the magnitude (length) squared
+      And once the magnitude squared is > 4, then magnitude > 2 is also true (saves computational power)
+    *************************************************************************************************/
+
+    // The pixel coordinates are scaled so they are on the mandelbrot scale
+    // NOTE: fragTexCoord already comes as normalized screen coordinates but offset must be normalized before scaling and zoom
+    vec2 z = vec2((fragTexCoord.x - 0.5)*2.5, (fragTexCoord.y - 0.5)*1.5)/zoom;
+    z.x += offset.x;
+    z.y += offset.y;
+
+    int iter = 0;
+    for (int iterations = 0; iterations < maxIterations; iterations++)
+    {
+        z = ComplexSquare(z) + c;  // Iterate function
+        if (dot(z, z) > 4.0) break;
+
+        iter = iterations;
+    }
+
+    // Another few iterations decreases errors in the smoothing calculation
+    // See http://linas.org/art-gallery/escape/escape.html for more information
+    z = ComplexSquare(z) + c;
+    z = ComplexSquare(z) + c;
+
+    // This last part smooths the color (again see link above)
+    float smoothVal = float(iter) + 1.0 - (log(log(length(z)))/log(2.0));
+
+    // Normalize the value so it is between 0 and 1
+    float norm = smoothVal/float(maxIterations);
+
+    // If in set, color black. 0.999 allows for some float accuracy error
+    if (norm > 0.999) gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
+    else gl_FragColor = vec4(Hsv2rgb(vec3(norm*colorCycles, 1.0, 1.0)), 1.0);
+}