Corrected handling of sf::View zoom. Refactored OpenGL display code.
Textures are now correctly displayed.
All SPARK stuff have been moved to a dedicaced ParticleSystemWrapper class.
Decomposed extension declaration in 3 files as GCC is not able to compile it in one file without filling all memory ( Windows Seven / 4 GB ).
git-svn-id: svn://localhost@275 8062f311-0dae-4547-b526-b8ab9ac864a5