Remove some unnecessary includes as well as simplifying exisiting ones if possible.

Source/Core/VideoBackends/OGL/Src/GLUtil.cpp

@@ -6,7 +6,6 @@
 #include "VideoConfig.h"
 #include "IniFile.h"
 #include "Core.h"
-#include "Host.h"
 #include "VideoBackend.h"
 #include "ConfigManager.h"
 

Source/Core/VideoBackends/OGL/Src/Render.cpp

@@ -28,7 +28,6 @@
 #include "ImageWrite.h"
 #include "PixelEngine.h"
 #include "Render.h"
-#include "OpcodeDecoding.h"
 #include "BPStructs.h"
 #include "TextureCache.h"
 #include "RasterFont.h"
@@ -49,7 +48,6 @@
 #include "Debugger.h"
 #include "Core.h"
 #include "Movie.h"
-#include "Host.h"
 #include "BPFunctions.h"
 #include "FPSCounter.h"
 #include "ConfigManager.h"

Source/Core/VideoBackends/OGL/Src/TextureConverter.cpp

@@ -5,8 +5,6 @@
 // Fast image conversion using OpenGL shaders.
 // This kind of stuff would be a LOT nicer with OpenCL.
 
-#include <math.h>
-
 #include "TextureConverter.h"
 #include "TextureConversionShader.h"
 #include "TextureCache.h"

Source/Core/VideoBackends/OGL/Src/VertexManager.cpp

@@ -24,7 +24,6 @@
 #include "VertexLoader.h"
 #include "VertexManager.h"
 #include "IndexGenerator.h"
-#include "OpcodeDecoding.h"
 #include "FileUtil.h"
 #include "Debugger.h"
 #include "StreamBuffer.h"