Renamed cImage::Size() to cImage::MemSize(), since it was confusing.

cImage::Size() now returns the image dimensions.
Changed how cUIControl::SetSkin works, it was confusing, now just spects a Skin const reference and make a copy from it.
Fixed DoAfterSetTheme to be virtual, now SetSkin works for all the controls.
Restructured cPrimitives.
Removed some Draw* calls, since it was a little bit bloated, sometimes less is more.
Also added fill mode, blend mode and line width as members of the instance of the primitives class, this way i reduced the number of parameters in almost all the functions, and, it's cleaner.

src/examples/empty_window/empty_window.cpp

@@ -32,7 +32,7 @@ EE_MAIN_FUNC int main (int argc, char * argv [])
 			}
 
 			// Draw a circle
-			p.DrawCircle( win->GetWidth() / 2, win->GetHeight() / 2, 200 );
+			p.DrawCircle( eeVector2f( win->GetWidth() * 0.5f, win->GetHeight() * 0.5f ), 200 );
 
 			// Draw frame
 			win->Display();