Shader uniforms keep their values after love.window.setMode (resolves issue #1174).

Also allow arrays of images/samplers in shaders, although driver support is iffy and you have to index into the array using a compile-time constant (which might exclude loop indexing).

--HG--
branch : minor

src/modules/graphics/opengl/Canvas.cpp

@@ -151,6 +151,9 @@ Canvas::~Canvas()
 
 bool Canvas::loadVolatile()
 {
+	if (texture != 0)
+		return true;
+
 	OpenGL::TempDebugGroup debuggroup("Canvas load");
 
 	fbo = texture = 0;