Makes joystick button ordering predictable.

Fixes unpredictable or unintentional joystick button ordering by sorting
buttons according to their HID Usage property.  This allows SFML to
adhere to a manufacturer's (or driver implentation's) intended button
ordering.
Recompiled dependencies on Windows to fix linker errors when compiling static libs with static runtime
Minor modification to the API doc
Fixed Xlib potential errors
Renamed RenderTarget::convertCoords to mapPixelToCoords, and added its inverse mapCoordsToPixel
Don't create std::string on glCheckError unless necessary.
Merge pull request #317 from cforfang/master

Speedup for debugging: don't create std::string on every call to glCheckError
Merge branch 'master' of github.com:LaurentGomila/SFML
Removed the endianness detection macros (were not used)
Moved some functions of RenderTarget to private access
Updated the description of modules
Updated the main page of the API documentation
Correction in the API documentation
Correction in the API documentation
Fixed example in the API doc of sf::SocketSelector
Disabled fix #271 for ogg cracks (the solution slows down the loading too much)
Improved the success message in FindSFML.cmake
Minor modification to the API documentation
Fixed the repeated keys detection algorithm on Linux
Fixed computation of the alpha channel in sf::BlendAdd