metal: nogame and error screens work.

- implement love.graphics.setColor
- implement default textures
- hacky implementation of default uniform data
- use texture swizzles to set up LA8 (text) texture data
- shader reflection work

src/modules/graphics/opengl/Graphics.cpp

@@ -149,7 +149,7 @@ love::graphics::StreamBuffer *Graphics::newStreamBuffer(BufferType type, size_t
 
 love::graphics::Texture *Graphics::newTexture(const Texture::Settings &settings, const Texture::Slices *data)
 {
-	return new Texture(settings, data);
+	return new Texture(this, settings, data);
 }
 
 love::graphics::ShaderStage *Graphics::newShaderStageInternal(ShaderStage::StageType stage, const std::string &cachekey, const std::string &source, bool gles)

src/modules/graphics/opengl/Texture.cpp

@@ -188,8 +188,8 @@ static GLenum newRenderbuffer(int width, int height, int &samples, PixelFormat p
 	return status;
 }
 
-Texture::Texture(const Settings &settings, const Slices *data)
-	: love::graphics::Texture(settings, data)
+Texture::Texture(love::graphics::Graphics *gfx, const Settings &settings, const Slices *data)
+	: love::graphics::Texture(gfx, settings, data)
 	, slices(settings.type)
 	, fbo(0)
 	, texture(0)

src/modules/graphics/opengl/Texture.h

@@ -38,7 +38,7 @@ class Texture final : public love::graphics::Texture, public Volatile
 {
 public:
 
-	Texture(const Settings &settings, const Slices *data);
+	Texture(love::graphics::Graphics *gfx, const Settings &settings, const Slices *data);
 
 	virtual ~Texture();