Fixed undefined behavior of returned pointer
Fixed some uninitialized values
Avoid const_cast, static buffer and buffer overlap
Merge pull request #431 from Kratos714/master

Fixed some minor memory issues
Updated version number
Fix typo (close #438)
Changed the default value of SFML_INSTALL_PKGCONFIG_FILES to FALSE (the generated pkg-config files contain local paths and thus are not suitable for distribution)
Merge branch 'master' of github.com:LaurentGomila/SFML
Updated OpenAL to version 1.15.1