Add initial video playback support for Ogg Theora videos (resolves issue #66.)

The basic APIs are:

video = love.graphics.newVideo("myvideo.ogv")

love.graphics.draw(video, ...) -- Video objects are Drawables.

video:play(), video:pause()

video:getDuration(), video:tell(), video:rewind(), video:seek(seconds)

video:getSource()

video:getWidth(), video:getHeight(), video:setFilter(min, mag)

More advanced APIs include video:setSource(source), video:getStream(), and videostream:setSync.

To use a custom pixel shader when drawing a Video, call the new TexelVideo(texcoords) function instead of Texel(texture, texcoords) in order to get the pixel colors of a video frame.

src/modules/graphics/opengl/Graphics.h

@@ -37,6 +37,8 @@
 
 #include "window/Window.h"
 
+#include "video/VideoStream.h"
+
 #include "Font.h"
 #include "Image.h"
 #include "graphics/Quad.h"
@@ -47,6 +49,7 @@
 #include "Shader.h"
 #include "Mesh.h"
 #include "Text.h"
+#include "Video.h"
 
 namespace love
 {
@@ -185,6 +188,8 @@ public:
 
 	Text *newText(Font *font, const std::vector<Font::ColoredString> &text = {});
 
+	Video *newVideo(love::video::VideoStream *stream);
+
 	bool isGammaCorrect() const;
 
 	/**