Replaced text overlay with proper (imgui based) UI overlay class

data/shaders/base/uioverlay.frag

@@ -0,0 +1,13 @@
+#version 450
+
+layout (binding = 0) uniform sampler2D fontSampler;
+
+layout (location = 0) in vec2 inUV;
+layout (location = 1) in vec4 inColor;
+
+layout (location = 0) out vec4 outColor;
+
+void main() 
+{
+	outColor = inColor * texture(fontSampler, inUV);
+}