remove all instances of round()

VS2008 doesn't have round() in math.h and the old inline function (removed
in 50d1413d, had problems in newer compilers). Now floor() or straight
casting to int is used. Let's see, which MS compiler will trip on that...

source/src/rendergl.cpp

@@ -1155,7 +1155,7 @@ void gl_drawframe(int w, int h, float changelod, float curfps)
     tagclipcubes.setsize(0);
 
     extern vector<vertex> verts;
-    gl_drawhud(w, h, (int)round(curfps), nquads, verts.length(), underwater);
+    gl_drawhud(w, h, int(curfps + 0.5f), nquads, verts.length(), underwater);
 
     glEnable(GL_CULL_FACE);
     glEnable(GL_FOG);