Fix of http://bitbucket.org/bartbes/love-fbo/issue/7

Move fbo:grab() to love.graphics.setRenderTarget( fbo )
Move fbo:stop() to love.graphics.setRenderTarget( nil )

Rename fbo:render( func ) to fbo:renderTo( func )

src/modules/graphics/opengl/wrap_Graphics.h

@@ -84,6 +84,7 @@ namespace opengl
 	int w_getPointStyle(lua_State * L);
 	int w_getMaxPointSize(lua_State * L);
 	int w_newScreenshot(lua_State * L);
+	int w_setRenderTarget(lua_State * L);
 	int w_draw(lua_State * L);
 	int w_drawq(lua_State * L);
 	int w_drawTest(lua_State * L);