Option to disable OpenGL error checking

[Lignum]

Hi,

I've recently used SFML again in a long time, where I used OpenGL directly. While debugging the application with gDEBugger, I noticed that any texture related code (for which I used sf::Texture) was calling glGetError a lot. Since there is the general concept of anything glGet* being evil in OpenGL, I fear that this might impact performance. It'd be nice to be able to toggle these glGetError calls on and off, or maybe even have them enabled only when using a debug context (i.e. sf::ContextSettings::Attribute::Debug).

[Laurent]

They are disabled in release builds.

[Lignum]

They are disabled in release builds.

Huh, I thought I tested in a release build... I tried again just now and they're indeed gone. I probably messed something up with my gDEBugger project. Well, thanks for pointing that out!