Fix screenshots under Linux/OpenGL for formats ECF_R5G6B5 (failed before) and ECF_R8G8B8 (red and blue where switched). Note that R5G6B5 still has strange results when writing to file. But that's due to a bug in color-conversion, which is fixed already in 1.7 and will be merged to trunk soon.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4185 dfc29bdd-3216-0410-991c-e03cc46cb475