Removed the extra surface in GLTexture. Now there are copies of the texture data in their original format (so engine can get the original data when lockScreen or grabOverlay is called). This copies will be updated when the engine calls a function that modifies the game screen/overlay, and the textures will be marked as dirty. When updating screen, the textures will be updated from the copies data if they are dirty.
svn-id: r51234
Passing a 'call statement' to CHECK_GL_ERROR has various issues.
For once, it confuses code parsers in many editors and other
tools that work with C++ source directly.
Moreover, this can lead to subtle bugs if a mistake is
made with the definition of CHECK_GL_ERROR.
It also causes incorrect warnings if CHECK_GL_ERROR is
used with an "empty" call statement.
svn-id: r51050
